1 © 2004 Cisco Systems, Inc. All rights reserved. RST-2602 9908_06_2004_X2 DEPLOYING MPLS-VPN...

1© 2004 Cisco Systems, Inc. All rights reserved.

RST-26029908_06_2004_X2

DEPLOYING MPLS-VPN

SESSION RST-2602

Rajiv Asati ([email protected])


RST-26029908_06_2004_X2

Agenda

• MPLS VPN Definition?Technology

Configuration

• MPLS-VPN Services Providing load-shared traffic to the multihomed VPN sites

Providing Hub&Spoke service to the VPN customers

Providing MPLS VPN Extranet service

Providing Internet access service to VPN customers

Providing VRF-selection based services

Providing Remote Access MPLS VPN

Providing VRF-aware NAT services

• Advanced MPLS VPN TopicsInter-AS MPLS-VPN

CsC Carrier Supporting Carrier

• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

Prerequisites

• Must understand basic IP routing, especially BGP

• Must understand MPLS basics (push, pop, swap, label stacking)

• Must finish the evaluation

http://www.networkers04.com/desktop


RST-26029908_06_2004_X2

Terminology:

• LSR : Label Switch Router

• LSP : Label Switched Path

The chain of labels that are swapped at each hop to get from one LSR to another

• VRF : VPN Routing and Forwarding

Mechanism in IOS used to build per-interface RIB and FIB

• MP-BGP: Multi-Protocol BGP

• PE : Provider Edge router Interfaces with CE routers

• P : Provider (core) router, without knowledge of VPN

• VPNv4 : Address family used in BGP to carry MPLS-VPN routes

• RD : Route Distinguisher

Distinguish same network/mask prefix in different VRFs

• RT : Route Target

Extended Community attribute used to control import and export policies of VPN routes

• LFIB : Label Forwarding Information Base

• FIB : Forwarding Information Base (FIB)


RST-26029908_06_2004_X2

Agenda


Configuration










• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

MPLS-VPN Operation’s Theory

• VPN definition: VRF instance

• VPN Route Propagation (Control Plane)

• VPN Packet forwarding (Data Plane)


RST-26029908_06_2004_X2

MPLS VPN Connection Model

PE

VPN Backbone IGP

MP-iBGP session

PE

P P

P P

PE routers

Edge Routers

Use MPLS with P routers

Uses IP with CE routers

Connects to both CE and P routers.Distribute VPN information through MP-BGP to other PE router with VPN-IPv4 addresses, Extended Community, Label

P Routers

P routers are in the core of the MPLS cloud

P routers do not need to run BGP and doesn’t need to have any VPN knowledge

Forward packets by looking at labels

P and PE routers share a common IGP


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MPLS VPN: Separate Routing Tables in PE

The Global routing table

Populated by the MPLS backbone IGP

In PE routers may contain the BGP Internet routes (standard ipv4 routes)

CE

PE

CE EBGP,OSPF, RIPv2,Static

vpn site 1

vpn site 2

MPLS Backbone IGP (OSPF, ISIS)

VRF routing table

Routing (RIB) and Forwarding table (CEF) associated with one or more directly connected sites (CEs)

The routes the PE receives from CE Routers are installed in the appropriate VRF routing table(s)

blue VRF routing table or green VRF routing table


RST-26029908_06_2004_X2

VRF: Virtual Routing and Forwarding Instance

• What’s a VRF ?

• Associates to one or more interfaces on PE

Privatize an interface i.e. coloring of the interface

• Has its own routing table and forwarding table (CEF)

• VRF has its own instance for the routing protocol

(static ,RIP,BGP,EIGRP,OSPF)

• CE router runs standard routing software

CE

PE


vpn site 1

vpn site 2


VRF blue

VRF green


RST-26029908_06_2004_X2

CE

PE


vpn site 1

vpn site 2


VRF: Virtual Routing and Forwarding Instance

• PE installs the routes, learned from CE routers, in the appropriate VRF routing table(s)

• PE installs the IGP (backbone) routes in the global routing table

• VPN customers can use overlapping IP addresses.


RST-26029908_06_2004_X2

Additions in BGP: MPLS-VPN Info BGP

• RD: Route Distinguisher

• VPNv4 routes

• RT: Route Target

• Label

8 Bytes

Route-Target

3 Bytes

Label

MP-iBGP update with RD, RT, and Label

1:1

8 Bytes 4 Bytes

RD IPv4VPNv4

10.1.1.0


RST-26029908_06_2004_X2

MPLS VPN Control Plane MP-BGP Update Components: VPNv4 address

• To convert an IPv4 address into a VPNv4 address, RD is appended to the IPv4 address i.e 1:1:10.1.1.0

• Makes the customer’s IPv4 route globally unique.

• Each VRF must be configured with an RD at the PE• RD is what that defines the VRF

8 Bytes

Route-Target

3 Bytes

Label

MP-IBGP update with RD, RT, and Label

1:1

8 Bytes 4 Bytes

RD IPv4VPNv4

10.1.1.0

!ip vrf v1 rd 1:1!

Cisco

Animation


RST-26029908_06_2004_X2

MPLS VPN Control Plane MP-BGP Update Components: Route-Target

• Route-target (RT): Identifies the VRF for the received VPNv4 prefix. It is an 8-byte extended Community (a BGP attribute)

• Each VRF is configured with RT(s) at the PE

RT helps to color the prefix

8 Bytes

Route-Target

3 Bytes

Label


1:1

8 Bytes 4 Bytes

RD IPv4VPNv4

10.1.1.0 2:2

!ip vrf v1 route-target import 1:1 route-target export 1:2!

Cisco

Animation


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MPLS VPN Control Plane MP-BGP Update Components: Label

• The Label (for the VPNv4 prefix) is assigned only by the PE whose address is the Next-Hop attribute

PE routers re-write the Next-Hop with their own address (loopback)

“Next-Hop-Self” towards MP-iBGP neighbors by default

• PE addresses used as BGP Next-Hop must be uniquely known in the backbone IGP

DO NOT summarize the PE loopback addresses in the core

8 Bytes

Route-Target

3 Bytes

Label


1:1

8 Bytes 4 Bytes

RD IPv4VPNv4

10.1.1.0 2:2 50

Cisco

Animation


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MPLS VPN Control Plane: Putting It All Together

10.10.1.0/24

Next-Hop=CE-1

MP-iBGP update:RD:10.10.1.0

Next-hop=PE-1RT=Green, Label=100

1

3

10.1.1.0/24

PE1 PE2P

P P

P

CE2CE1

MPLS Backbone

Site 1 Site 2

1) PE1 receives an IPv4 update (eBGP,OSPF,EIGRP)

2) PE1 translates it into VPNv4 address• Assigns an RT per VRF configuration• Re-writes Next-Hop attribute to itself• Assigns a label based on VRF and/or interface

3) PE1 sends MP-iBGP UPDATE to other PE routers

Cisco

Animation


RST-26029908_06_2004_X2

5

10.1.1.0/24

Next-Hop=CE-1

MP-iBGP update:RD:10.10.1.0

Next-hop=PE-1RT=Green, Label=100

1

3

10.1.1.0/24

PE1 PE2P

P P

P

CE2CE1

MPLS Backbone

Site 1 Site 2

10.1.1.0/24

Next-Hop=PE-2

4) PE2 receives and checks whether the RT=green is locally configured within any VRF, if yes, then

5) PE2 translates VPNv4 prefix back into IPv4 prefix,

• Installs the prefix into the VRF Routing table

• Updates the VRF CEF table with label=100 for 10.1.1.0/24

• Advertise this IPv4 prefix to CE2 (EBGP, OSPF, EIGRP)

MPLS VPN Control Plane: Putting It All Together

Cisco

Animation


RST-26029908_06_2004_X2

10.1.1.0/24

PE1 PE2P2

P P

P1

CE2CE1

Site 1 Site 2

Global routing/forwarding tableDest->Next-HopPE2 P1, label: 50

Global routing/forwarding tableDest->NextHopPE1 P2, label: 25

VRF Green forwarding Table Dest->NextHop 10.1.1.0/24-PE1, label: 100

e

VRF Forwarding table (show ip cef vrf <vrf>)

•PE routers store VPN routes•Associated labels•Labels distributed through MP-BGP

The Global Forwarding table (show ip cef)

•PE routers store IGP routes•Associated labels•Label distributed through LDP/TDP

MPLS VPN Forwarding Plane:


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PE2 imposes TWO labels for each packet going to the VPN destination 10.1.1.1

• The top label is LDP learned and Derived from an IGP route

Represents LSP to PE address (exit point of a VPN route)

• The second label is learned via MP-BGP

Corresponds to the VPN address

10.1.1.0/24

PE1 PE2

CE2CE1

Site 1 Site 2e

10.1.1.110.1.1.1

MPLS VPN Forwarding Plane:

P

P P

P

10.1.1.11002510.1.1.110050

10.1.1.1100

Cisco

Animation


RST-26029908_06_2004_X2

Agenda


Configuration










• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

MPLS VPN Sample Configuration

ip vrf VPN-Ard 1:1route-target export 100:1route-target import 100:1

Interface Serial0ip address 192.168.10.1 255.255.255.0ip vrf forwarding VPN-A

VRF Definition

PE-P Configuration

P

PE1s1

Interface Serial1ip address 130.130.1.1 255.255.255.252mpls ip

router ospf 1network 130.130.1.0 0.0.0.3 area 0

10.1.1.0/24

PE1

CE1

Site 1

192.168.10.1

Se0

Se0

PE1

PE1

Cisco

Animation


RST-26029908_06_2004_X2


router bgp 1 neighbor 1.2.3.4 remote-as 1 neighbor 1.2.3.4 update-source loopback 0

address-family vpnv4 neighbor 1.2.3.4 activate neighbor 1.2.3.4 send-community both

PE: MP-IBGP

RR: MP-IBGP router bgp 1no bgp default route-target filterneighbor 1.2.3.6 remote-as 1neighbor 1.2.3.6 update-source loopback0

address-family vpnv4neighbor 1.2.3.6 route-reflector-clientNeighbor 1.2.3.6 activate

PE1 PE2

RR

PE1 PE2

RR

PE1

RR

Cisco

Animation


RST-26029908_06_2004_X2


router bgp 1!address-family ipv4 vrf VPN-A neighbor 192.168.10.2 remote-as 2 neighbor 192.168.10.2 activate exit-address-family!

PE-CE BGP

PE-CE OSPFrouter ospf 1!router ospf 2 vrf VPN-Anetwork 192.168.10.0 0.0.0.255 area 0!

10.1.1.0/24

PE1

CE1

Site 1

192.168.10.1

192.168.10.2

10.1.1.0/24

PE1

CE1

Site 1

192.168.10.1

192.168.10.2

PE1

PE1

Cisco

Animation


RST-26029908_06_2004_X2


router rip

address-family ipv4 vrf VPN-A version 2 no auto-summary network 192.168.10.0 exit-address-family

PE-CE RIP

PE-CE EIGRProuter eigrp 1

address-family ipv4 vrf VPN-A network 192.168.10.0 0.0.0.255 autonomous-system 1 exit-address-family

10.1.1.0/24

PE1

CE1

Site 1

192.168.10.1

192.168.10.2

10.1.1.0/24

PE1

CE1

Site 1

192.168.10.1

192.168.10.2

Cisco

Animation


RST-26029908_06_2004_X2


ip route vrf VPN-A 10.1.1.0 255.255.255.0 192.168.10.2

PE-CE Static

PE-CE MB-iBGP routes to VPNrouter rip address-family ipv4 vrf VPN-A version 2 redistribute bgp 1 metric 1 no auto-summary network 192.168.10.0 exit-address-family

10.1.1.0/24

PE1

CE1

Site 1

192.168.10.1

192.168.10.2

If PE-CE protocol is non BGP then redistribution of other sites VPN routes from MP-IBGP is required.

PE1

RR

CE1

Site 1

Cisco

Animation


RST-26029908_06_2004_X2


router bgp 1 neighbor 1.2.3.4 remote-as 1 neighbor 1.2.3.4 update-source loopback 0

address-family ipv4 vrf VPN-A redistribute {rip|connected|static|eigrp|ospf}

PE-RR (VPN routes to VPNv4)

PE1

RR

CE1

Site 1

If PE-CE protocol is non BGP then redistribution of other sites VPN routes into MP-IBGP is required.

Cisco

Animation


RST-26029908_06_2004_X2

Agenda


Configuration










• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

MPLS VPN Services:1. Loadsharing for the VPN traffic

• VPN sites (such as Site A) could be multihomed

• VPN customer may demand the traffic to the multihomed sites be loadshared

PE11

PE2

MPLS Backbone

PE12

CE1

Site A

171.68.2.0/24

Site B

CE2

RR

Route Advertisement


RST-26029908_06_2004_X2

MPLS VPN Services:1. Loadsharing for the VPN traffic: Cases

PE11

PE2

MPLS Backbone

PE12

CE1

Site A

171.68.2.0/24

Site B

CE2

RR

Traffic Flow

RR

PE11

PE2

MPLS Backbone

PE12

CE1

Site A

171.68.2.0/24

Site B

CE2

CE2

Traffic Flow

1 CE 2 PEs

2 CEs 2 PEs


RST-26029908_06_2004_X2

MPLS VPN Services:1. Loadsharing for the VPN Traffic: Deployment

How to deploy the loadsharing ?

1. Configure different VRFs i.e RDs for multihomed site/interfaces.

2. Enable BGP multipath within the relevant BGP VRF address-family at Remote/Receiving PE2.

PE11

PE2

MPLS BackbonePE12

CE1

Site A

171.68.2.0/24

Site B

CE2

RRip vrf greenrd 300:11route-target both 1:1

ip vrf greenrd 300:12route-target both 1:1

router bgp 1address-family ipv4 vrf greenmaximum-paths eibgp 2

1

1

2

ip vrf greenrd 300:13route-target both 1:1

1

Cisco

Animation


RST-26029908_06_2004_X2

MPLS VPN Services:1. Loadsharing for the VPN Traffic（实验）

• RR must advertise all the paths learned via PE11 and PE12 to the remote PE routers

With different RD per VRF, RR does the Best path calculation per RD and advertise them to remote PE

• Watch out for the increased (~20%) memory consumption (within BGP) due to multipaths at the PEs

• “eiBGP multipath” implicitly provides eBGP and iBGP multipath for VPN paths

PE11

PE2

MPLS Backbone

PE12

CE1

Site A

171.68.2.0/24

Site B

CE2

RRRoute Advertisement


RST-26029908_06_2004_X2

MPLS-VPN Services: 2. Hub & Spoke Service to the VPN Customers

• Traditionally, VPN deployments are Hub&Spoke.

Spoke to spoke communication is via Hub site only.

• Despite MPLS VPN’s implicit any-to-any i.e full-mesh connectivity, Hub&Spoke service can easily be offered.

Done with import and export of Route-Target (RT).


RST-26029908_06_2004_X2

MPLS-VPN Services: 2. Hub & Spoke Service - Configuration

PE-SA

PE-Hub

MPLS VPN Backbone

PE-SB

CE-SA

CE-SBSpoke B

Spoke A

171.68.1.0/24

171.68.2.0/24

Eth0/0.2

Eth0/0.1

ip vrf green-spoke1description VRF for SPOKE Ard 300:111route-target export 1:1route-target import 2:2

ip vrf green-spoke2description VRF for SPOKE Brd 300:112route-target export 1:1route-target import 2:2

ip vrf HUB-OUTdescription VRF for traffic from HUBrd 300:11route-target import 1:1

ip vrf HUB-INdescription VRF for traffic to HUB rd 300:12route-target export 2:2

Cisco

Animation


RST-26029908_06_2004_X2

MPLS-VPN Services: 2. Hub & Spoke Service – Control Plane

PE-SA

MPLS Backbone

PE-SB

CE-SA

CE-SB

Spoke B

Spoke A

VRF HUB-IN

VRF HUB-OUT

VRF HUB-OUT RT and LFIBDestination NextHop Label171.68.1.0/24 PE-SA 40171.68.2.0/24 PE-SB 50

171.68.1.0/24

171.68.2.0/24

• All traffic between spokes must pass through the Hub/Central Site.Hub Site could offer FireWall, NAT like applications.

• Two VRF solution at the PE-Hub: • VRF HUB_OUT would have knowledge of every spoke routes.• VRF HUB_IN only have Default Route and advertise that to Spoke PEs.

• Import and export Route-Target within a VRF must be different.

PE-Hub

VRF HUB-IN Routing TableDestination NextHop0.0.0.0 CE-H1

Adv 0.0.0.0Label 35Route-Target 2:2

Adv 171.68.2.0/24Label 50Route-Target 1:1

Adv 171.68.1.0/24Label 40 Route-Target 1:1

VRF RT and LFIB at PE-SA0.0.0.0 PE-Hub 35171.68.1.0/24 CE-SA

VRF RT and LFIB at PE-SB0.0.0.0 PE-Hub 35171.68.2.0/24 CE-SB

Cisco

Animation


RST-26029908_06_2004_X2

PE-SA

PE-Hub

MPLS Backbone

PE-SB

CE-SA

CE-SBSpoke B

Spoke A

VRF HUB-IN

VRF HUB-OUT

171.68.1.0/24

171.68.2.0/24

171.68.1.1

LH 35 171.68.1.1

LA 40 171.68.1.1

171.68.1.1

MPLS-VPN Services(实验内容 ): 2. Hub & Spoke Service – Forwarding Plane

Cisco

Animation


RST-26029908_06_2004_X2

MPLS-VPN Services3. Extranet VPN

• MPLS VPN, by default, isolates one VPN customer from another.

Separate Virtual Routing Table for each VPN customer

• Communication between VPNs may be required i.e. Extranet.

External Inter-company communication (dealers with manufacturer, Retailer with wholesale provider etc)

Management VPN, Shared-service VPN etc.

• Needs right import and export route-target (RT) values configuration within the VRFs

export-map or import-map should be used


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3. MPLS-VPN Services: Extranet VPNGoal: Only VPN_A site#1 to be reachable to VPN_B

171.68.0.0/16 PE1 PE2

MPLS Backbone

VPN_A Site#2

soP

VPN_A Site#1

VPN_B Site#1

180.1.0.0/16

ip vrf VPN_Ard 3000:111export map VPN_A_Export import map VPN_A_Importroute-target import 3000:111route-target export 3000:111route-target import 3000:1! route-map VPN_A_Export permit 10 match ip address 1 set extcommunity rt 3000:2!route-map VPN_A_Import permit 10 match ip address 2! access-list 1 permit 171.68.0.0 0.0.0.0access-list 2 permit 180.1.0.0 0.0.0.0

ip vrf VPN_Brd 3000:222export map VPN_B_Export import map VPN_B_Importroute-target import 3000:222route-target export 3000:222route-target import 3000:2! route-map VPN_B_Export permit 10 match ip address 2 set extcommunity rt 3000:1!route-map VPN_B_Import permit 10 match ip address 1! access-list 1 permit 171.68.0.0 0.0.0.0access-list 2 permit 180.1.0.0 0.0.0.0

192.6.0.0/16

Only Site#1 of both VPNs will communicate to each other, Site#2 won’t.

Cisco

Animation


RST-26029908_06_2004_X2

MPLS-VPN Services4. Internet Access Service to VPN Customers

• Could be provided as another value-added service.

• Security mechanism must be in place at both provider network and customer network

To protect from the Internet vulnerabilities

• VPN customers benefit from the single point of contact for both Intranet and Internet connectivity


RST-26029908_06_2004_X2

MPLS-VPN Services4. Internet Access: Different Methods of Service

• Four ways to provide the Internet service

1. VRF Specific default route with “global” keyword

2. Separate PE-CE sub-interface (nonVRF)

3. Extranet with Internet-VRF

4. VRF-aware NAT


RST-26029908_06_2004_X2

MPLS-VPN Services（实验内容）4. Internet Access: Different Methods of Service

1. VRF Specific default route

1.1 Static default route to move traffic from VRF to Internet (global routing table)

1.2 Static routes for VPN customers to move traffic from Internet (global routing table) to VRF

2. Separate PE-CE sub-interface (non VRF)

May run BGP to propagate Internet routes between PE and CE


VPN packets never leave VRF context ; issue with Overlapping VPN address

4. Extranet with Internet-VRF along with VRF-aware NAT

VPN packets never leave VRF context; works well with overlapping VPN address


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• A default route, pointing to the ASBR, is installed into the site VRF at each PE

A single label is used for packets forwarded according to the default route

The label is the IGP label corresponding to the IP address of the ASBR known via the IGP

• The static route, pointing to the VRF interface, is installed in the global routing table and redistributed into BGP

171.68.0.0/16PE1

ASBR

CE1

MPLS Backbone

192.168.1.1

Internet GW

so

Pip vrf VPN-Ard 100:1route-target both 100:1Interface Serial0ip address 192.168.10.1 255.255.255.0ip vrf forwarding VPN-A

Router bgp 100no bgp default ipv4-unicastredistribute staticneighbor 192.168.1.1 remote 100neighbor 192.168.1.1 activateneighbor 192.168.1.1 next-hop-selfneighbor 192.168.1.1 update-source loopback0

ip route vrf VPN-A 0.0.0.0 0.0.0.0 192.168.1.1 globalip route 171.68.0.0 255.255.0.0 Serial0

Site1

192.168.1.2

MPLS-VPN Services: 4.1 Internet access: VRF Specific Default Route (Config)

Internet

Cisco

Animation


RST-26029908_06_2004_X2

171.68.0.0/16

PE1 PE2

MPLS Backbone

192.168.1.1

so

P

VRF Routing/FIB Table

Destination Label/interface

0.0.0.0/0 192.168.1.1 (global)

Site-1 Serial 0

Global Routing/FIB Table

Destination Label/Interface

192.168.1.1/32 Label=30

171.68.0.0/16 Serial 0

IP packetD=Cisco.com

Label = 30 IP packetD=Cisco.com


IP packetD=171.68.1.1

Label = 35


Global Table and LFIB

Destination Label/Interface

192.168.1.2/32 Label=35

171.68.0.0/16 192.168.1.2

Internet Serial 0

192.168.1.2


Pros

Different Internet gatewayscan be used for different VRFs

PE routers need not to hold the Internet table

Simple Configuration

Cons

Using default route for Internetrouting does NOT allow any otherdefault route for intrA_VPN routing

Increasing size of global routing Table by leaking VPN routes.

Static configuration

Site1

so

MPLS-VPN Services: 4.1 Internet access: VRF Specific Default Route (Forwarding)

Internet

Cisco

Animation


RST-26029908_06_2004_X2

MPLS-VPN Services4.2 Internet Access

1. VRF Specific default route

1.1 Static default route to move traffic from VRF to Internet (global routing table)

1.2 Static routes for VPN customers to move traffic from Internet (global routing table) to VRF

2. Separate PE-CE sub-interface (non VRF)

May run BGP to propagate Internet routes between PE and CE


VPN packets never leave VRF context ; Overlapping VPN addresses could be a problem

4. Extranet with Internet-VRF alongwith VRF-aware NAT

VPN packets never leave VRF context; works well with overlapping VPN addresses


RST-26029908_06_2004_X2

ip vrf VPN-Ard 100:1route-target both 100:1Interface Serial0.1 ip vrf forwarding VPN-A ip address 192.168.20.1 255.255.255.0 frame-relay interface-dlci 100!Interface Serial0.2 ip address 171.68.10.1 255.255.255.0 frame-relay interface-dlci 200!

Router bgp 100no bgp default ipv4-unicast[snip]…neighbor 171.68.10.2 remote 502

4.2 Internet Access Service to VPN CustomersUsing Separate Sub-Interface (Config)

171.68.0.0/16

PE1 ASBR

CE1 MPLS Backbone

Internet GW

192.168.1.1S0.2

P

BGP-4

Site1

192.168.1.2

S0.1

One sub-interface for VPN routing associated to a VRF

Another sub-interface for Internet routing associated to the global routing table.

Could advertise full Internet Routes or a default route to CE.

The PE will need to advertise VPN routes to the Internet (via global routing table)

Internet Internet


RST-26029908_06_2004_X2

171.68.0.0/16

PE1 PE2

MPLS Backbone

PE-Internet GW

192.168.1.1S0.2

P

Site1

192.168.1.2

S0.1


CE routing tableVPN routes Serial0.1Internet routes Serial0.2

PE Global Table and FIBInternet routes 192.168.1.1192.168.1.1 Label=30

Label = 30 IP packetD=Cisco.com IP packet

D=cisco.com

Pros

CE could dual home and perform optimal routing.

Traffic separation done by CE.

Cons

PE to hold full Internet routes.

BGP complexities introduced in CE.

Internet Access Service to VPN Customers4.2 Using Separate Sub-Interface (Forwarding)

Internet

Cisco

Animation


RST-26029908_06_2004_X2

Internet Access Service4.3 Extranet with Internet-VRF

• The internet routes could be placed within the VRF at the Internet-GW i.e. ASBR

• VRFs for customers could ‘extranet’ with the internet VRF and receive either default, partial or full internet routes

• Be careful if duplicating the internet routes in each VRF

• Works well when the VPN customers don’t have overlapping addresses


RST-26029908_06_2004_X2

Internet Access Service4.4 Internet Access using VRF-aware NAT

• If the VPN customers need Internet access without internet routes, then VRF-aware NAT can be used at the Internet-GW i.e. ASBR

• The Internet GW doesn’t need to have internet routes either

• Overlapping VPN addresses is not a problem

• More in the “VRF-aware NAT” slides,…..


RST-26029908_06_2004_X2

MPLS VPN Service5. VRF-Selection

• The common notion is that the VRF must be associated to an interface

• “VRF-selection” breaks this association and associate multiple VRFs to an interface

• Each packet on the PE-CE interface could be handled (based on certain criteria) via different VRF routing tables

Criteria such as source/dest IP address, ToS, TCP port etc. specified via route-map

• Voice and Data can be separated out into different VRFs at the PE


RST-26029908_06_2004_X2

MPLS VPN Service5. VRF-Selection – Based on Source IP Address

PE1PE2

MPLS Backbone(Cable Company)CE1

RR

44.3.12.1

66.3.0.0/16

VPN Green

44.3.0.0/16

VPN Blue

33.3.0.0/16

VPN Brown

66.3.1.25

33.3.14.1

Global Interface

Se0/0

CableSetup

VRF Interfaces

Traffic Flows

ip vrf brown rd 3000:111 route-target export 3000:1 route-target import 3000:1!ip vrf blue rd 3000:222 route-target export 3000:2 route-target import 3000:2!ip vrf green rd 3000:333 route-target export 3000:3 route-target import 3000:3

route-map PBR-VRF-Selection permit 10 match ip address 40 set vrf brown

route-map PBR-VRF-Selection permit 20 match ip address 50 set vrf blue

route-map PBR-VRF-Selection permit 30 match ip address 60 set vrf green

interface Serial0/0 ip address 215.2.0.6 255.255.255.252 ip policy route-map PBR-VRF-Selection ip receive brown ip receive blue ip receive green

access-list 40 permit 33.3.0.0 0.0.255.255access-list 50 permit 44.3.0.0 0.0.255.255access-list 60 permit 66.3.0.0 0.0.255.255

Cisco

Animation


RST-26029908_06_2004_X2

MPLS VPN Service6. Remote Access Service

• Remote access users i.e. dial users, IPSec users could directly be terminated in VRF

PPP users can be terminated into VRFs

IPSec tunnels can be terminated into VRFs

• Remote Access services integration with MPLS VPN opens up new opportunities for Providers


RST-26029908_06_2004_X2

Internet

MPLS VPN Service6. Remote Access Service– IPSec to MPLS VPN

Internet

Corporate IntranetCorporate IntranetBranchBranchOfficeOffice AccessAccess

Remote Users/ Telecommuters

MPLS VPNIPSec SessionIP IP

Cable/DSL/ISDN ISP

IP/MPLS/Layer 2Based Network

VPN A

VPN B

SP Shared NetworkSP Shared Network

Customer B

Customer Ahead office

Customer C

PEPE

PEPE

VPN C

SOHO

Local or Direct Dial ISP

Cisco IOS VPN Routers or Cisco Client 3.x or higher Customer A

branch office

PEPE

SP AAA Customer AAAPE+IPSec

Aggregator

VPN A

Cisco

Animation


RST-26029908_06_2004_X2

MPLS-VPN Services7. VRF-Aware NAT Services

• VPN customers could be using ‘overlapping’ IP address i.e. 10.0.0.0/8

• Such VPN customers must NAT their traffic before using either “extranet” or “internet” or any shared* services

• PE is capable of NATting the VPN packets (eliminating the need for an extra NAT device)

* VoIP, Hosted Content, Management etc/


RST-26029908_06_2004_X2

MPLS-VPN Services7. VRF-Aware NAT Services

• Typically, inside interface(s) connect to private address space and outside interface connect to global address space

NAT occurs after routing for traffic from inside-to-outside interfaces

NAT occurs before routing for traffic from outside-to-inside interfaces

• Each NAT entry is associated with the VRF

• Works on VPN packets in the following switch paths : IP->IP, IP->MPLS and MPLS->IP


RST-26029908_06_2004_X2

Internet

MPLS-VPN Services:7. VRF-Aware NAT Services – Internet Access

PE11

PE-ASBR

MPLS Backbone

PE12

CE1

Blue VPN Site

10.1.1.0/24

P

CE2

10.1.1.0/24

Green VPN Site

ip nat inside

ip nat outside

217.34.42.2.1

VRF-aware NAT Specific ConfigVRF specific Config

ip nat pool pool-green 24.1.1.0 24.1.1.254 prefix-length 24

ip nat pool pool-blue 25.1.1.0 25.1.1.254 prefix-length 24

ip nat inside source list vpn-to-nat pool pool-green vrf greenip nat inside source list vpn-to-nat pool pool-blue vrf blue

ip access-list standard vpn-to-nat permit 10.1.1.0 0.0.0.255

ip route vrf green 0.0.0.0 0.0.0.0 217.34.42.2 globalip route vrf blue 0.0.0.0 0.0.0.0 217.34.42.2 global

ip vrf green rd 3000:111 route-target both 3000:1ip vrf blue rd 3000:222 route-target both 3000:2

router bgp 3000 address-family ipv4 vrf green network 0.0.0.0 address-family ipv4 vrf blue network 0.0.0.0

Cisco

Animation


RST-26029908_06_2004_X2

MPLS-VPN Services:7. VRF-Aware NAT Services – Internet Access

• This is also one of the ways to provide Internet access to VPN customers with or without overlapping addresses

PE11 PE-ASBR

MPLS Backbone

PE12

CE1

Blue VPN Site

10.1.1.0/24

P

CE2

Traffic Flows

10.1.1.0/24

Green VPN Site

Src=10.1.1.1 Dest=Internet




Label=30 Src=10.1.1.1 Dest=Internet

Label=40 Src=10.1.1.1 Dest=Internet

IP Packet

MPLS Packet

IP Packet

NAT TableVRF IP Source Global IP VRF-table-id10.1.1.1 24.1.1.1 green10.1.1.1 25.1.1.1 blue

•PE-ASBR removes the label from the received MPLS packets per LFIB

•Performs NAT on the resulting IP packets

•Forwards the packet

Internet

Cisco

Animation


RST-26029908_06_2004_X2

Agenda


Configuration










• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

What Is Inter-AS?

VPN-AVPN-A

PE-1

PE2

CE2 CE-1

AS #1AS #2

149.27.2.0/24

MP-iBGP update::MP-iBGP update::

BGP, OSPF, RIPv2 149.27.2.0/24,NH=CE-1

BGP, OSPF, RIPv2 149.27.2.0/24,NH=CE-1

Problem:

How do Provider X and Provider Y exchange VPN

routes ?

???ASBR1 ASBR2

RR2RR1

Provider X Provider Y

Cisco

Animation


RST-26029908_06_2004_X2

Inter-AS Deployment Scenarios

VPN-A

PE1

VPN-A

PE2

CE2

1. Back-to-back VRFs

2. MP-eBGP for VPNv4

3. Multihop MP-eBGP between RRs

4. Non-VPN Transit Provider

Following options/Scenarios for deploying Inter-AS :Following options/Scenarios for deploying Inter-AS :

AS #1 AS #2

ASBR1 ASBR2

CE1

•2 and 3 are more common and will be discussed. 1 and 4 are in backup slides.

Cisco

Animation


RST-26029908_06_2004_X2

Scenario 2: MP-eBGP between ASBRs to Exchange VPNv4 Routes

• New CLI “no bgp default route-target filter” is needed on the ASBRs.

• ASBRs exchange VPN routes using eBGP (VPNv4 af)

• ASBRs store all VPN routes –

But only in BGP table and LFIB table

Not in routing nor in CEF table

• ASBRs don’t need -

VRFs to be configured on them

LDP between them


RST-26029908_06_2004_X2

Scenario 2: MP-eBGP bet ASBRs for VPNv4Control Plane （实验内容）

PE-1 PE-2

VPN-B

CE-2 CE-3

VPN-B

ASBR-1 ASBR-2

10.1.1.0/24

BGP, OSPF, RIPv2 10.1.1.0/24, NH=CE-2BGP, OSPF, RIPv2

10.1.1.0/24, NH=CE-2

MP-iBGP update:RD:1:27:10.1.1.0/24, NH=PE-1RT=1:1, Label=(40)

MP-iBGP update:RD:1:27:10.1.1.0/24, NH=PE-1RT=1:1, Label=(40)

MP-iBGP update:RD:1:27:10.1.1.0/24, NH=ASBR-2RT=1:1, Label=(30)

MP-iBGP update:RD:1:27:10.1.1.0/24, NH=ASBR-2RT=1:1, Label=(30)

BGP, OSPF, RIPv2 10.1.1.0/24, NH=PE-2 BGP, OSPF, RIPv2

10.1.1.0/24, NH=PE-2

MP-eBGP update:RD:1:27:10.1.1.0/24, NH=ASBR-1RT=1:1, Label=(20)

MP-eBGP update:RD:1:27:10.1.1.0/24, NH=ASBR-1RT=1:1, Label=(20)

Cisco

Animation


RST-26029908_06_2004_X2

Scenario 2: MP-eBGP bet ASBRs for VPNv4Forwarding Plane

PE-1PE-2

VPN-BCE-2 CE-3

VPN-B

ASBR-1 ASBR-2

10.1.1.0/24

10.1.1.1

10.1.1.130

20 10.1.1.110.1.1.140

10.1.1.1

10.1.1.13020

10.1.1.14030

P1

P2

MPLS Packets between ASBRsMPLS Packets

between ASBRs

•More scalable.Only one interface between ASBRs routersNo VRF configuration on ASBR.Less memory consumption (no RIB/FIB memory)

•MPLS label switching between providersStill simple, more scalable & works today

Pros Cons•Automatic Route Filtering must be disabled

But we can apply BGP filtering.

•ASBRs are still required to hold VPN routes

Cisco

Animation


RST-26029908_06_2004_X2

Cisco IOS Configuration Scenario 2: External MP-BGP between ASBRs for VPNv4（实验内容）

VPN-A

PE1

VPN-A

PE2

CE-2CE-1

ASBR1 ASBR2

AS #1 AS #2

MP-eBGP for VPNv4

Label exchange between ASBRs using

MP-eBGP

1.1.1.0/30

Note: ASBR must already have MP-iBGP session with iBGP neighbors such as RRs or PEs.

Router bgp xno bgp default route-target filterneighbor 1.1.1.x remote-as x!address-family vpnv4neighbor 1.1.1.x activateneighbor 1.1.1.x send-com extended

ASBR MB-EBGP Configuration

Cisco

Animation


RST-26029908_06_2004_X2

Scenario 3: Multihop MP-eBGP between RRs to exchange VPNv4 routes

• Exchange VPNv4 prefixes via the Route Reflectors

Requires Multihop MP-eBGP (with next-hop-unchanged)

• Exchange IPv4 routes with labels between directly connected ASBRs using eBGP

Only PE loopback addresses need to be exchanged (they are BGP next-hop addresses of the VPN routes)


RST-26029908_06_2004_X2

Scenario 3: Multihop MP-eBGP between RRs for VPN routes : Control Plane

PE-1 PE-2

VPN-B

CE-2

CE-3

VPN-B

ASBR-1

RR-2

AS#2ASBR-2

RR-1

IP-v4 update: Network=PE-1 NH=ASBR-1Label=(20)

IP-v4 update: Network=PE-1 NH=ASBR-1Label=(20)

BGP, OSPF, RIPv2 10.1.1.0/24,NH=CE-2BGP, OSPF, RIPv2 10.1.1.0/24,NH=CE-2

10.1.1.0/24

VPN-v4 update:RD:1:27:10.1.1.0/24, NH=PE-1RT=1:1, Label=(90)






BGP, OSPF, RIPv2 10.1.1.0/24,NH=PE-2BGP, OSPF, RIPv2 10.1.1.0/24,NH=PE-2

AS#1

IGP+LDP: Network=PE-1 NH=ASBR-2Label=(30)

IGP+LDP: Network=PE-1 NH=ASBR-2Label=(30)

IGP+LDP: Network=PE-1 NH=PE-1Label=(40)

IGP+LDP: Network=PE-1 NH=PE-1Label=(40)

Note - Instead of IGP+Label, iBGP+Label can be used to exchange PE routes/label. Please see Scenario#5 on slide#49 and 50.

Cisco

Animation


RST-26029908_06_2004_X2

Scenario 3: Multihop MP-eBGP between RRs for VPN routes : Forwarding Plane

PE-1

PE-2

VPN-B

CE-2 CE-3

VPN-B

RR-2

ASBR-2

RR-1

10.1.1.0/24

10.1.1.1

90 10.1.1.130

20 90 10.1.1.1

10.1.1.190

10.1.1.1

50 90 10.1.1.1

40 90 10.1.1.1

ASBR-1

P1 P2

Note - Instead of IGP+Label, iBGP+Label can be used to exchange PE routes/label.

Cisco

Animation


RST-26029908_06_2004_X2

Scenario 3: Pros/Cons

Pros Cons•More scalable than Scenario 1 and 2.

Separation of control and forwarding planes

•Route Reflector exchange VPNv4 routes+labels RR hold the VPNv4 information anyway

•ASBRs now exchange only IPv4 routes+labelsASBR Forwards MPLS packets

•Advertising PE addresses to another AS may not be acceptable to few providers.


RST-26029908_06_2004_X2

Cisco IOS Configuration Scenario 3: Multihop MP-eBGP between RRs for VPNv4（实验）

VPN-A

PE1

VPN-A

PE2

CE-2

CE-1

ASBR-1

RR-2

AS #1 AS #2

Multihop MP-eBGP for VPNv4 with

next-hop-unchange

ASBR-2

RR-1

eBGP IPv4 + Labels

iBGPipv4+label could also be used in within each AS (instead of “network <x.x.x.x>”) to propagate the label information for PEs.

router ospf xredistribute bgp 1 subnets!router bgp xneighbor < ASBR-x > remote-as x!address-family ipv4Network <PEx> mask 255.255.255.255Network <RRx> mask 255.255.255.255neighbor < ASBR-x > activateneighbor < ASBR-x > send-label

router bgp xneighbor <RR-x> remote-as xneighbor <RR-x> ebgp-multihopneighbor <RR-x> update loopback 0!address-family vpnv4neighbor <RR-x> activateneighbor <RR-x> send-com extendedneighbor <RR-x> next-hop-unchanged

RR Configuration ASBR Configuration

Cisco

Animation


RST-26029908_06_2004_X2

Inter-AS Deployment Guidelines

1. Use ASN in the Route-target i.e. ASN:xxxx

2. Max-prefix limit (both BGP and VRF) on PEs

3. Security (BGP MD5, BGP filtering, BGP max-prefix etc) on ASBRs

4. End-to-end QoS agreement on ASBRs

5. Route-Target rewrite on ASBR

6. Internet connectivity on the same ASBR ??


RST-26029908_06_2004_X2

Agenda


Configuration










• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

Carrier Supporting Carriers: CsC

• Benefits of CsC

• What do I need to do to enable CsC ?

• Deployment models

• Security in CsC

• Deployment Guideline

• Deployment Scenarios


RST-26029908_06_2004_X2

MPLS/VPN Networks without CsC

• Unwanted routing updates in the Carrier’s network => CPU+memory

• Label/prefix consumptions at PE => memory

• Scalability issue at PE

Large Number of VPN Routes at the PE May Pose Limitation to the PE


RST-26029908_06_2004_X2

MPLS/VPN Networks without CsC

• The no of VPN routes is one of the biggest limiting factor in scaling the PE router

Few SPs are running into this scalaing limitation

• If no of VPN routes can be reduced somehow (without loosing the functionality), then the existing investment can be protected

The same PE can still be used to connect more VPN customers

• Carrier Supporting Carrier (CsC) provides the mechanism to reduce the no of routes from each VRF by enabling MPLS on the PE-CE link


RST-26029908_06_2004_X2

Benefits of CsC

• Provide transport for ISPs ($)

No need to manage external routes from ISPs

• Build MPLS Internet Exchange (MPLS-IX) ($$)

Media Independence; POS/FDDI/PPP possible

Higher speed such OC192 or more

Operational benefits

• Sell VPN service to subsidiary companies that provide VPN service ($)


RST-26029908_06_2004_X2

What Do I Need to Enable CsC ?

1. Build an MPLS-VPN enabled carrier’s network

2. Connect ISP/SPs sites (or PoPs) to the Carrier’s PEs

3. Exchange internal routes + labels between Carrier’s PE & ISP/SP’s CE

4. Exchange external routes directly between ISP/SP’s sites


RST-26029908_06_2004_X2

CsC Deployment Models

PE1 PE2

ISP PoPSite-1

CE-1CE-2

IPv4 routes with label distributionIPv4 routes with label distribution

ISP PoPSite-2

MP-iBGP for VPNv4MP-iBGP for VPNv4

Carrier’s MPLS Core

P1

ASBR-2

R1

R2

ISP customers = external routes

Full-mesh iBGP for external routes

Full-mesh iBGP for external routes

IPv4 routes with label distributionIPv4 routes with label distribution

ASBR-1

internal routes = IGP routes

internal routes = IGP routes

Internal routes = IGP routes

Internal routes = IGP routes

IGP+LDPIGP+LDPIGP+LDPIGP+LDP

INTERNET

C1

MPLS enabled VRF int

Cisco

Animation


RST-26029908_06_2004_X2

CsC Deployment Models

1. Customer-ISP not running MPLS

2. Customer-ISP running MPLS

3. Customer-ISP running MPLS-VPN

•Model 1 and 2 are less common deployments.•Model 3 will be discussed in detail.


RST-26029908_06_2004_X2

PE1 PE2

ISP PoPSite-1

CE-1CE-2

30.1.61.25/32, NH=CE-1, Label = 50

30.1.61.25/32, NH=CE-1, Label = 50

30.1.61.25/32, NH=PE-2, Label = 52

30.1.61.25/32, NH=PE-2, Label = 52

ISP PoPSite-2

MP-iBGP update:1:1:30.1.61.25/32, RT=1:1NH =PE-1, Label=51

MP-iBGP update:1:1:30.1.61.25/32, RT=1:1NH =PE-1, Label=51

Carrier’s Core

P1

ASBR_PE-1 30.1.61.25/32

ASBR_PE-2

R1R2

Network = 10.1.1.0/24

MP-iBGP update:1:1:10.1.1.0/24, RT=1:1 NH =30.1.61.25/32, Label = 90

MP-iBGP update:1:1:10.1.1.0/24, RT=1:1 NH =30.1.61.25/32, Label = 90

IGP+LDP, Net=PE-1, Label = pop

IGP+LDP, Net=PE-1, Label = 16

VPN Site-2

10.1.1.0/24, NH=R1 10.1.1.0/24, NH=R1

10.1.1.0/24, NH =ASBR_PE-2

10.1.1.0/24, NH =ASBR_PE-2

IGP+LDP 30.1.61.25/32,Label = pop

IGP+LDP 30.1.61.25/32,Label = pop

IGP+LDP, 30.1.61.25/32

NH=CE-2, Label=60

IGP+LDP, 30.1.61.25/32

NH=CE-2, Label=60

IGP+LDP, 30.1.61.25/32 NH=C1,

Label=70

IGP+LDP, 30.1.61.25/32 NH=C1,

Label=70

VPN Site-1

C1

CsC: ISP Sites Are Running MPLS-VPN Hierarchical MPLS-VPN Control Plane

Cisco

Animation


RST-26029908_06_2004_X2

PE1

PE2

ISP PoPSite-1

CE-1CE-2

ISP PoPSite-2

Carrier’s Core

P1

ASBR-1 ASBR-2

R1 R2Network = 10.1.1.0/24

10.1.1.110.1.1.110.1.1.19070

10.1.1.19050

10.1.1.1905116

10.1.1.19052

10.1.1.19060

10.1.1.19051

10.1.1.190

VPN Site-1 VPN Site-2

C1

CsC: ISP Sites Are Running MPLS-VPN Hierarchical MPLS-VPN Forwarding Plane

Cisco

Animation


RST-26029908_06_2004_X2

Security Mechanism in CsC

• BGP/LDP MD5 on PE-CE

To prevent label “spoofing”, PE

• Maintains Label <=> VRF table association

• Checks during LFIB lookup that received packet’s label is what was allocated

If the check fails, then the packet is dropped.


RST-26029908_06_2004_X2

CsC Deployment Guideline

• Two choices for deploying CsC

1. IGP+LDP on the PE-CE, or

2. eBGP ipv4 +label on the PE-CE (RFC3107)

• Choice selection is driven by the choice of routing protocol on the PE-CE

• CE has to run MPLS-aware code


RST-26029908_06_2004_X2

CsC: IOS Commands/Configs Choice 1: What All You Need to Configure?

• Sh mpls interface [vrf <name>] all

Sh mpls ldp disc [vrf <name>] all

Sh mpls ldp bind vrf <name>

Sh mpls ip bind vrf <name>

Sh mpls ldp neighbor [vrf <name>] all

Sh mpls forward [vrf <name>]

int ser0/0

ip vrf forwarding green

mpls ip

mpls ldp protcol ldp

int ser0/0

mpls ip

mpls ldp protcol ldp

Sh mpls interface

Sh mpls ldp discovery

Sh mpls ldp bind

Sh mpls ldp neighbor

Sh mpls forward

Choice1: Enable LDP on PE-CE;

PE-1

CE-1

VRF Int

IGP+LDP

PE1

CE1


RST-26029908_06_2004_X2

CsC: IOS Commands/ConfigsChoice 2: What All You Need to Configure?

router bgp 1

address-family ip vrf green

neighbor 200.1.61.6 remote-as 2

neighbor 200.1.61.6 send-label

router bgp 2

neighbor 200.1.61.5 remote-as 1

neighbor 200.1.61.5 send-label

Choice2: Enable eBGP+label on PE-CE;

PE-1

CE-1

eBGP+label

VRF Int

1. No IGP needed on PE-CE 2. No LDP needed on PE-CE

PE1

CE1


RST-26029908_06_2004_X2

IOS Commands/ConfigsChoice 2: eBGP+label on the PE-CE

• On PE

Sh ip bgp vpn vrf <vrf> neighbor

Sh ip bgp vpn vrf <vrf> label

Sh mpls forward vrf <vrf>

• On CE

Sh ip bgp neighbor

Sh ip bgp labels

Sh mpls forward


RST-26029908_06_2004_X2

Agenda


Configuration










• Best Practices

• Conclusion.


RST-26029908_06_2004_X2

Best Practices

1. Use RR to scale BGP.

2. Deploy RRs in pair for the redundancy

3. Keep RRs out of the forwarding paths and disable CEF (saves memory).

4. Consider Unique RD per VRF per PE, if Load sharing of VPN traffic is reqd.

5. RT and RD should have ASN in them i.e. ASN : X

Reserve first few 100s of X for the internal purposes such as filtering

6. Don't use customer names as the VRF names; Nightmare for the NOC. Use simple combination of numbers and characters in the VRF name

For example - v101, v102, v201, v202 etc. Use description.

7. Define an upper limit at the PE on the # of prefixes received from the CE for each VRF or neighbor

max-prefix within the VRF configuration

max-prefix per neighbor within the BGP VRF af (if BGP on the PE-CE)


RST-26029908_06_2004_X2

Conclusion

• MPLS VPN is a cheaper alternative to traditional l2vpn

• MPLS-VPN paves the way for new revenue streams

VPN customers could outsource their layer3 to the provider

• Straightforward to configure any-to-any VPN topology

partial-mesh, hub&spoke topologies can also be easily deployed

• CsC and Inter-AS could be used to expand into new markets

• VRF-aware services could be deployed to maximize the investment


RST-26029908_06_2004_X2

Complete Your Online Session Evaluation!

WHAT: Complete an online session evaluation and your name will be entered into a daily drawing

WHY: Win fabulous prizes! Give us your feedback!

WHERE: Go to the Internet stations located throughout the Convention Center

HOW: Winners will be posted on the onsiteNetworkers Website; four winners per day

http://www.networkers04.com/desktop


RST-26029908_06_2004_X2

Thanks for your time.

Q & A

Eval -http://www.networkers04.com/desktop


RST-26029908_06_2004_X2


RST-26029908_06_2004_X2

BACK UP SLIDES


RST-26029908_06_2004_X2

Scenario 1: Back-to-back VRF Control Plane

PE-1 PE-2

VPN-B

CE-2 CE-3

VPN-B

VRF to VRF Connectivity between ASBRs VRF to VRF Connectivity between ASBRs

ASBR-1 ASBR-2

10.1.1.0/24

BGP, OSPF, RIPv2 10.1.1.0/24,NH=CE-2BGP, OSPF, RIPv2 10.1.1.0/24,NH=CE-2

VPN-v4 update:RD:1:27:10.1.1.0/24 NH=PE-1RT=1:1, Label=(29)

VPN-v4 update:RD:1:27:10.1.1.0/24 NH=PE-1RT=1:1, Label=(29)

VPN-B VRFImport routes with

route-target 1:1

BGP, OSPF, RIPv2 10.1.1.0/24 NH=ASBR-2

BGP, OSPF, RIPv2 10.1.1.0/24 NH=ASBR-2

VPN-v4 update:RD:1:27:10.1.1.0/24, NH=ASBR-2RT=1:1, Label=(92)

VPN-v4 update:RD:1:27:10.1.1.0/24, NH=ASBR-2RT=1:1, Label=(92)

VPN-B VRFImport routes with

route-target 1:1

BGP, OSPF, RIPv2 10.1.1.0/24,NH=PE-2BGP, OSPF, RIPv2 10.1.1.0/24,NH=PE-2

Cisco

Animation


RST-26029908_06_2004_X2

•Not scalable. #of interface on both ASBRs is directly proportional to #VRF.•No end-to-end MPLS. •Unnecessary memory consumed in RIB/(L)FIB •Dual-homing of ASBR makes provisioning worse

Scenario 1: Back-to-back VRF Forwarding Plane

PE-1 PE-2

VPN-B

CE-2 CE-3

VPN-B

ASBR-1 ASBR-2

10.1.1.0/24

10.1.1.1

10.1.1.1

10.1.1.1

10.1.1.12930

10.1.1.19220

P2

P1

10.1.1.192

IP Packets between ASBRs

IP Packets between ASBRs

•Per-customer QoS is possible

•It is simple and elegant since no need to load the Inter-AS code (but still not widely deployed).

Pros Cons

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Cisco IOS ConfigurationScenario 1: Back-to-Back VRF between ASBRs

AS #1 AS #2VRF routes exchange via

any routing protocol

Note: ASBR must already have MP-iBGP session with iBGP neighbors such as RRs or PEs.

1.1.1.0/30

ip vrf green rd 1:1 route-target both 1:1!Router bgp xAddress-family ipv4 vrf greenneighbor 1.1.1.x activate

ASBR VRF and BGP config

VPN-A

PE1

CE-1

VPN-A

CE-2

PE2

ASBR1 ASBR2

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VPN-A

PE1

VPN-A

PE2

CE-2 CE-1

ASBR1 ASBR2

AS #1 AS #2

Multi-Hop MP-eBGP for VPNv4

IGP & LDP

interface serial 0ip address 1.1.1.x/30mpls ldp protcol ldp

router bgp xno bgp default route-target filterneighbor < ASBR-x > remote-as xneighbor < ASBR-x > update loopback0neighbor < ASBR-x > ebgp-multihop!address-family vpnv4neighbor < ASBR-x > activateneighbor < ASBR-x > send-comm extended

Multi-Hop MP-BGP session between ASBRs

so so

IOS Configuration Scenario 2.5: Multi-Hop MP-eBGP for VPNv4

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Scenario 4: Non-VPN Transit Provider

• Two MPLS VPN providers may exchange routes via one or more transit providers

Which may be non-VPN transit backbones just running MPLS

• Multihop MP-eBGP deployed between edge providers

With the exchange of BGP next-hops via the transit provider


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Option 4: Non-VPN Transit Provider

PE1

PE2VPN-B

CE-2

CE-3

VPN-B

ASBR-1

RR-2

Non-VPN MPLS Transit Backbone

Multihop MP-eBGP OR

MP-iBGP for VPNv4

ASBR-2

RR-1

ASBR-3

ASBR-4 next-hop-unchanged

eBGP IPv4 + Labels

eBGP IPv4 + Labels

MPLS VPN Provider #1

MPLS VPN Provider #2

iBGP IPv4 + Labels

iBGP IPv4 + Labels

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Route-Target rewrite at ASBR

• ASBR can add/delete route-target associated with a VPNv4 prefix

• Secures the VPN environment

ASBR(conf)#router bgp 1000

ASBR(conf-router)#neighbor 1.1.1.1 route-map route-target-deletion out

ASBR(conf-router)#exit

ASBR(conf)#route-map route-target-delete

ASBR(conf-route-map)#match extcommunity 101

ASBR(conf-route-map)#set extcomm-list 101 delete

ASBR(conf-route-map)#set extcommunity rt 123:123 additive

ASBR(conf)# ip extcommunity-list 101 permit rt 100:100

1 © 2004 Cisco Systems, Inc. All rights reserved. RST-2602 9908_06_2004_X2 DEPLOYING MPLS-VPN...

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Transcript of 1 © 2004 Cisco Systems, Inc. All rights reserved. RST-2602 9908_06_2004_X2 DEPLOYING MPLS-VPN...