Abstract This white paper is a technology overview discussing the use of EMC RAPIDPath to increase network availability and utilization of the wide area network (WAN) links between EMC VPLEX Metro over IP or EMC VPLEX Geo clusters.

Deploying EMC RAPIDPath with EMC VPLEX Metro IP and VPLEX Geo

Copyright © 2011-2012 EMC Corporation. All Rights Reserved.

EMC believes the information in this publication is accurate of its publication date. The information is subject to change without notice. The information in this publication is provided “as is.” EMC Corporation makes no representations or warranties of any kind with respect to the information in this publication, and specifically disclaims implied warranties of merchantability or fitness for a particular purpose. Use, copying, and distribution of any EMC software described in this publication requires an applicable software license. For the most up-to-date listing of EMC product names, see EMC Corporation Trademarks on EMC.com. VMware is a registered trademark of VMware, Inc. All other trademarks used herein are the property of their respective owners.

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Table of Contents

Executive summary.................................................................................................. 4 Document scope and limitations ........................................................................................ 7 Audience ............................................................................................................................ 7

VPLEX IP WAN Com overview .................................................................................... 8

EMC RAPIDPath technology .................................................................................... 10 RAPIDPath Hardware & Port assignments ......................................................................... 11 RAPIDPath Peering ............................................................................................................ 12

Solution topologies for VPLEX and RAPIDPath ......................................................... 12 Using VLANs to Manage your Environment: ...................................................................... 13 GRE Tunneling with RAPIDPath Multihomed Multipathing ................................................. 13

Configuration considerations for VPLEX and RAPIDPath .......................................... 15

Deploying RAPIDPath with VPLEX Metro-IP and Geo ................................................ 16

Conclusion ............................................................................................................ 17

Appendix-A: RAPIDPath Related Terminology and Definitions .................................. 18

Appendix-B: RAPIDPath and VPLEX Firewall/Port Requirements .............................. 19

Appendix-C: Reference Documentation .................................................................. 19

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Executive summary The EMC® VPLEX™ family removes physical barriers within, across, and between data centers. VPLEX Local provides simplified management and non-disruptive data mobility across heterogeneous arrays. VPLEX Metro and Geo provide data access and mobility between two VPLEX clusters within synchronous and asynchronous distances respectively. With a unique scale-up architecture, VPLEX’s advanced data caching and distributed cache coherency provide workload resiliency, automatic sharing, and balancing and failover of storage domains, and enable both local and remote data access with predictable service levels. For the purpose of this paper, the focus of new technology EMC® RAPIDPath as it relates to VPLEX is around Metro over IP and Geo configurations.

• VPLEX Metro for mobility and access across two locations separated by inter-site RTT of up to 10

ms. VPLEX Metro uses two VPLEX clusters and includes the unique capability where a remote VPLEX Metro cluster can present LUNs without the need for physical storage for those LUNs at the remote cluster. It also supports synchronous distributed volumes that mirror data between the two clusters using write-through caching. VPLEX Metro supports FC or Ethernet WAN Com. RAPIDPath is only supported with VPLEX Metro over IP (VPLEX Metro IP)

• VPLEX Geo, which also uses two VPLEX clusters, for access between two sites over extended

asynchronous distances with RTT latencies up to 50 ms. VPLEX Geo distributed volumes support AccessAnywhere distributed mirroring using write-back caching.

When implementing distance replication and reliability dependent applications, customers have to consider their current network environments between Data Centers. Some of the current challenges and solutions that may exist in those networks are as follows:

• Network conditions cause poor performance over distance. These conditions ultimately will contribute to higher latencies and packet loss.

• When there is congestion on a network path, there is no way to avoid sending packets through the congested equipment. This problem can also contribute to higher latencies and packet loss resulting in unwanted packet retransmissions.

• Common network configurations rely on an Active-Passive network setup, wasting time,

money, and other resources on a network link that may never be used. This approach can be quite expensive when all the costs of duplicate and unused equipment are counted up.

As the amount of data that is replicated between data centers grows, so does the bandwidth requirements. There are many technologies to help offset the cost of increasing the size of their WAN circuits through technologies such as congestion control, network congestion avoidance (802.11), QOS, and packet shaping (or throttling). One major disadvantage to these related technologies is that 802.11, QOS, and Packet Shaping are all dependent on the entire end-to-end network path being able to honor and implement the same standards over long haul connections or Internet lines. In most cases there will be multiple carriers that do not honor these standards between in point in their own networks. As a result these techniques can help in local networks but typically not in the WAN network path.

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Other technologies such as compression and de-duplication may also be used to improve speed and reliability between data centers, but may only help in instances when you sending compressible or repetitive traffic patterns across networks. If your traffic is already compressed or non-compressible, and non-repetitive then you will see little to no benefit in traffic reduction across the WAN path. The game changer in all of these instances is EMC® RAPIDPath. EMC® RAPIDPath is an appliance that optimizes TCP and UDP (UDT) based network traffic between data centers using three main mechanisms: Intelligent Transport, TCP Optimization, and Multihomed Multipathing. These EMC® RAPIDPath technologies work between layer 3 and 4, adding the intelligence to choose between multiple paths for the best path for each packet, while also taking away the congestion control and loss recovery of the native protocol and substituting the algorithms of EMC® RAPIDPath. The RAPID protocol is designed with highly efficient congestion control and loss recovery so that network conditions have the least amount of protocol impact as possible.

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Time Figure-1a: No Intelligent Transport Figure-1b: With Intelligent Transport Without the Intelligent Transport each TCP connection has to find the ideal throughput by trial and error where there is a slow and gradual build of traffic which will overload the path and then follow by a drop in throughput as seen in Figure-1a. With RAPIDPath, once the initial connections have been established the RAPID protocol will quickly and efficiently determine the maximum throughput possible and then will maintain these throughputs until congestion is detected. Then The RAPID protocol will make small adjustments while reacting quickly to regain throughput as seen in the above in Figure-1b. To provide WAN optimization, the RAPIDPath appliance is deployed in each data center and all incoming/outgoing traffic to be optimized must pass through the RAPIDPath appliance before entering or exiting the WAN network. All WAN traffic is wrapped in the RAPID protocol, controlled by Intelligent Transport. As soon as TCP packets are received they are acknowledged, the appliance takes responsibility for getting the data to the other side. The key benefit from using RAPIDPath optimization is that it will prevent the WAN condition from reducing WAN throughput unnecessarily between data centers because RAPIDPath is controlling the outcome instead of standard TCP protocol standards. Figure-2a and Figure-2b show the differences between RAPID protocol optimized traffic vs. non-optimized WAN traffic.

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Figure-2a: Not Optimized Figure-2b: Optimized EMC® RAPIDPath allows customers to make all WAN links active and intelligently manages traffic across all network paths. This allows customers to fully utilize all bandwidth in multiple link configurations and provides continuous availability. In the event of a link failure, RAPIDPath intelligently routes traffic over the other link without breaking network connectivity or requiring a WAN failover. Additionally, RAPIDPath manages multiple IP flows across any single physical connection, improving throughput up to 40 percent on degraded network connections.

Figure-3: Typical Multihomed Multipathing Configuration

EMC® RAPIDPath Intelligent Transport and Multihomed Multipathing features work to alleviate the impact of both network latency and lost packets on VPLEX WAN Com traffic. Typically redundancy of WAN links is implemented as an Active-Passive pair, where the passive link is reserved for use in the event of failure of the Primary link. With RAPIDPath Multihomed Multipathing, both WAN links are utilized as one to get the maximum flow of data regardless of the differing characteristics of the two links. In addition, the loss of a single WAN link is transparent to VPLEX requiring no fault handling by VPLEX. The Intelligent Transport feature provides VPLEX the optimal utilization of the links between clusters by overcoming some of the shortcomings of normal network protocols. RAPIDPath also supports the use of additional WAN optimization technology from companies such as Ciena, Cisco, Riverbed, and SilverPeak.

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The primary use cases for this type solution specific to VPLEX are: • Provide increased tolerance to single path failures by utilizing both active links. By using both

data paths your VPLEX Metro-Ip and/or VPLEX Geo configurations to be fully redundant in the case of a path or component failure.

• Using RAPIDPath in your environment will provides up to a 40% performance increase for VPLEX

Metro-IP and VPLEX Geo configurations. This paper reviews the technical considerations and the necessary procedural adjustments when using VPLEX with RAPIDPath. The key takeaway for each of these use cases is RAPIDPath and VPLEX can be combined into a solution that delivers on the strengths of both products. This white paper is divided up into the following sections:

• VPLEX IP WAN Com overview • EMC RAPIDPath technology • Solution topologies for EMC VPLEX and EMC RAPIDPath • Configuration considerations for VPLEX and RAPIDPath • Deploying RAPIDPath with VPLEX Metro-IP and Geo

This white paper is designed to give technology decision-makers a deeper understanding of VPLEX and RAPIDPath design, features, and functionality. This paper highlights the key technical considerations for implementing RAPIDPath with VPLEX technology to achieve a more optimal and resilient utilization of WAN infrastructure between VPLEX Metro IP or VPLEX Geo clusters. The integration of the two products results in a solution that helps VPLEX dissolve distance more efficiently and with improved throughput.

Document scope and limitations This document applies to EMC VPLEX Metro IP and VPLEX Geo implemented with EMC RAPIDPath in the VPLEX WAN com path at both clusters. The details provided in this white paper are based on the following configurations:

• VPLEX Metro IP or VPLEX Geo (VPLEX Metro FC is not supported, Local does not apply) • VPLEX GeoSynchrony v5.1.0 and higher with VS2 hardware only • RAPIDPath v4.0 and higher

The use cases and procedures described are applicable for new and existing VPLEX customers planning to implement RAPIDPath with VPLEX Metro IP or VPLEX Geo. Please consult with your local EMC Support representative if you are uncertain as to the applicability of these procedures to your VPLEX environment.

Audience This white paper is intended for technology architects, network administrators, storage administrators, and EMC professional services partners who are responsible for architecting, creating, managing, and using IT environments that utilize EMC VPLEX technologies. The white paper assumes that the reader is familiar with EMC VPLEX technology.

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VPLEX IP WAN Com overview The VPLEX Metro and Geo architectures1 consist of two VPLEX clusters that use inter-cluster communications to facilitate the cache-coherent presentation of storage from both clusters. VPLEX Metro IP and VPLEX Geo use UDP based Data Transfer (UDT) for inter-cluster communications over IP networks. These communication links are sometimes referred to as WAN Com or IP WAN Com. The inter-cluster WAN Com traffic should be on a different network than the management traffic and requires two different networks with different subnets. Typically, each subnet utilizes one of the two required redundant physical links between the VPLEX clusters. Preferably distributed across two separate service providers to prevent a single point of failure (SPOF). Though the requirements and SLAs for WAN Com links may be clearly defined, real world experience indicates that latencies and packet loss can vary between different times of day as well as from link to link resulting in a negative impact that can potentially extend to the Host I/O performance on the VPLEX clusters. Note the following:

• WAN Com port group 0 and 1 (and associated subnets) should be isolated from each other. This can be accomplished by utilizing separate network gear or most commonly through the use of VLANs. Please see the section Using VLANs to manage your Environment below for more details.

• IP WAN connections in VS2 engines are optical 10 Gb/s Ethernet. These connections do not negotiate down to slower speeds. This means they must be connected to 10 Gb/s equipment (such as switches or routers). The connected equipment can then provide slower connection speeds down the line if required.

• The VPLEX IP WAN ports do not support trunking.

Each VPLEX engine contains two directors. Each director has a WAN Com port 0 (XG00) and port 1 (XG01) which are each assigned a static IP address. In addition, each port group is assigned a static IP address. The chart below indicates the number of WAN Com IP addresses required for various VPLEX cluster sizes.

VPLEX Cluster size

Number of static IP addresses required Per subnet (port group)

Per cluster

Single-engine 3 6 Dual-engine 5 10 Quad-engine 9 18

1 For more information on the complete VPLEX support family and topologies, including LOCAL; please refer to the Support page on Powerlink.

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The information in the chart below illustrates a sample configuration used by the EMC installation team to configure a VPLEX implementation that is set up for inter-cluster communication over IP.

Figure 4 - VPLEX Geo Routing Diagram

The following illustrates the typical components associated with VPLEX Metro-IP or VPLEX Geo environments and how they are configured without RAPIDPath.

Figure 5 - VPLEX Single Engine Typical WAN Com Diagram

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EMC RAPIDPath technology Intelligent Transport This feature utilizes a proprietary protocol based on UDP which we refer to as the RAPID protocol. Similar to TCP, RAPID is able to provide ordered, reliable transport of network information. Additionally, RAPID protocol uses an enhanced set of network congestion control algorithms that overcome common problems that exist in other network protocols. This allows the RAPIDPath appliance to fully utilize all of the available bandwidth on the wide area network connection and maintain high rates of transfer, even in networks with high loss and delay. For example, standard TCP places limitations on maximum window size that the receiver can advertise and reacts strongly to congestion related losses. This can limit your ability to reach your maximum amount of data on the circuit. Intelligent Transport solves this problem using an array of techniques, including the following:

• Opening multiple virtual transport layer connections. • Using more sophisticated congestion control. • Additional techniques for reliability and flow control.

Intelligent Transport was designed from the ground up to overcome these limitations and provide the best performance over network links possible. Using Intelligent Transport the appliance is able to provide optimization of both UDP and TCP based protocols. Connection details from previous connections are maintained, allowing connections to begin at the optimal throughput as soon as traffic begins to flow. Each loss in the network path is characterized and the reason a packet is lost is estimated based on the current throughput and the number of losses seen previously. Lost packets are selectively retransmitted, meaning the Rapid protocol will only retransmit packets that are dropped whereas TCP and UDP retransmit the dropped packet and all subsequent packets. The profiling of each network path, which includes loss rate, transmission time, ordering and current transfer rates, allows the system to identify congestion in the network and target the optimal throughput rate to fill the network path reliably. Multihomed Multipathing A unique technology provided by RAPIDPath is the ability to utilize multiple paths to send data to a destination. The technology built into our software allows us to take advantage of a technique we call Multihomed Multipathing.

Figure 6 - Typical RAPIDPath Multihomed Multipathing Configuration

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Networks are designed to be dynamic in nature, to adapt to failed segments. Because of this, data packets will not necessarily take the same network path between a source and destination. However, in the real world network traffic will tend to take a single path between sites. This is mainly due to methods used by service providers to route traffic over large networks. One byproduct of the fact that traffic tends to take a single path is that common network paths emerge and are used by massive amounts of data traffic running between service providers. The side effect is overloaded network components which causes dropped and delayed packets, and out of order delivery. These three consequences lead to decreased transfer rates. In the case of Multihomed Multipathing, we are able to form tunnel connections to edge routers at a datacenter and use both the primary point to point data link between sites and the backup connection simultaneously as two independent network paths. The RAPIDPath node then adjusts the amount of data placed on each connection to overcome points of congestion in either network path. If the primary connection has congestion causing packets to be dropped or delayed, more packets are placed on the secondary connection in such a way that the overall packets arrive in order at the other site. If there is no congestion on either path, both are utilized to their highest available capacity. The connections are dynamically balanced and if one were to fail, the network traffic would continue to flow uninterrupted on the remaining connection. RAPIDPath Multihomed Multipathing relies on and requires GRE Tunneling between each RAPIDPath appliance and the edge routers at the local site.

RAPIDPath Hardware & Port assignments

The RAPIDPath hardware utilizes a 1U form factor and is based on an Intel Xeon core processor and it may be racked in any customer provided rack. It can be ordered with 1Gbps (copper) or 10Gbps (fiber) Ethernet ports and these ports are all configured with “Fail-to-Wire” capability from the factory. The RAPIDPath appliance may be initialized via serial connection or by using a user supplied keyboard & monitor.

Figure 7 - RAPIDPath Hardware & Port Assignments

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Together the LAN and WAN ports, as shown in Figure 4, are referred to as the DATA port. The data port is assigned a single IP address and treated as a single entity in the UI. RAPIDPath determines through which physical port traffic should flow. The two physical ports act as a bridge between the LAN and the WAN, therefore these ports should be connected to the appropriate hardware to avoid creating a network loop. This can be accomplished by connecting to separate broadcast networks or separate VLANs. Please see the section Using VLANs to manage your Environment below for more details. Note: LAN and WAN VLANs must be different without the use of tagging. The Management port is used to access the Command Line Interface (CLI) and Web Interface GUI.

It is important to note that prior to physically cabling the RAPIDPath, you will want to prevent any potential bridging loops by taking extra precautions to ensure that both the LAN and WAN interfaces are NOT members of the same VLAN or broadcast network. This type of behavior may also be avoided by enabling the Spanning Tree Protocol (STP).

RAPIDPath Peering A RAPIDPath appliance must then be logically connected to another RAPIDPath appliance across the WAN in order to optimize data traffic between the two appliances. The RAPIDPath appliance located on the remote site is referred to as a Peer. Figure 5 shows the steps involved in a fully redundant implementation:

1) Build Peering relationship between RAPIDPath-1 (RD1) and RAPIDPath-2 (RD2) 2) Build Peering relationship between RAPIDPath-3 (RD3) and RAPIDPath-4 (RD4)

Figure 8 - RAPIDPath Peering

3) Enable ALL Peers

Solution topologies for VPLEX and RAPIDPath RAPIDPath improves the WAN COM traffic in VPLEX and thus helps the seamless replication of data across two VPLEX clusters. VPLEX requires redundant paths between Metro or Geo clusters. For optimizing the data traffic in a VPLEX environment, you must deploy a set of RAPIDPath appliance peers in each of these redundant data paths, one each at both the ends of the WAN links.

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It is important to note that before implementing RAPIDPath with VPLEX, the VPLEX must be in a healthy state. Care should be taken to verify the health of both VPLEX clusters prior to beginning the implementation of RAPIDPath into the VPLEX environment. As mentioned earlier, when implementing RAPIDPath into an environment, care should be taken to avoid creating a network or bridge loop with the WAN and LAN ports of the RAPIDPath Data Port. One method that can be used to avoid the bridge loop is the application of VLANs.

Using VLANs to Manage your Environment: Virtual Local Area Networks (VLANs) are commonly used to partition larger physical networks into smaller segments for logical grouping of ports and/or simplified management of networks. VLANs are created on either a layer-2 switches or layer-3 routers. In the VPLEX Metro-IP and VPLEX Geo environment the aggregation of WAN-Com ports by Port Groups will greatly simplify network design and management. A VLAN has the same attributes as a physical local area network (LAN), but it allows for end stations to be grouped together more easily even if they are not on the same network switch. Figure 9 illustrates a typical VLAN configuration for a single engine VPLEX and redundant RAPIDPath peers.

Figure 9 - Typical VLAN Configuration for VPLEX/RAPIDPath

NOTE: Without VLANs, a switch treats all interfaces on the switch to be in a single broadcast domain. NOTE: Trunking and VLAN Tagging are not currently supported with VPLEX and/or RAPIDPath.

GRE Tunneling with RAPIDPath Multihomed Multipathing The RAPIDPath Multihomed Multipathing feature relies on and requires GRE Tunneling and Policy Based Routing (PBR) between each RAPIDPath appliance and the edge routers at the local site. This is accomplished as follows:

1. Gather the IP Addresses for your environment in preparation for building the GRU Tunnels. This includes the WAN interface (DATA), the default gateway, and last hop gateway (Internet)

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2. As seen in Figure 10, Create Tunnel-1 between RAPIDPath-1's DATA port and the default gateway,

then using Service Provider #1's address as the next hop address to route to the external network.

Figure 10 - Creating GRE Tunnels 1 & 2

3. Create Tunnel-2 between RAPIDPath-1's DATA port and the default gateway, then using Service Provider #2's address as the next hop address to route to the external network.

Figure 11 - Creating GRE Tunnels 3 & 4

4. Repeat the process by creating Tunnels 3 & 4 for RAPIDPath-3. Now repeat these steps for

RAPIDPath Nodes 2 & 4 at the remote data center.

It is important to note: • The Tunnel configuration requires configuration on the routers as well as the RAPIDPath

appliances, starting with the routers. • Certain routers may not be able to handle the workload created by the RAPIDPath usage of these

tunnels. Consult the RAPIDPath Release notes for information about router requirements to support RAPIDPath usage of GRE Tunneling.

• MTU Sizing from “end-to-end” is essential for RAPIDPath to perform optimally.

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Configuration considerations for VPLEX and RAPIDPath It is important to note that certain adjustments may need to be made on the VPLEX and your underlying infrastructure devices for RAPIDPath and VPLEX to work optimally from end-to-end. The first setting is the MTU Size for each port in the VPLEX Port Groups. RAPIDPATH Intelligent Transport requires 100 of the MTU and the Multihomed Multipathing feature adds another 24 to that figure. So using the default of 1500 for the network MTU requires VPLEX MTU to be set to 1376, or 1400 without Multihomed Multipathing. For jumbo packets with an end-to-end MTU setting of 9000, for example, set the VPLEX MTU size to 8876 for Multihomed Multipathing and 8900 otherwise. Second, the Rebuild Size should be set as a “per-disk” setting used for initial rebuilds and mobility jobs. This setting requires special scrutiny because it could have an impact on your front-end connected hosts. So don't set it and forget it, be diligent to keep track and adjust as required. The third setting is the Socket Buffer Size. In Ethernet the maximum size data that will be transmitted in one go is determined by the Socket Buffer (SB) size. It forms a flow control mechanism. If the SB is too small VPLEX will be starved for packets and transmissions will take extra overhead. If the SB is too large then VPLEX will accumulate large internal queues, and IOs will not be processed efficiently. Thus the goal is to setup the SB size to be optimal for your configuration. Check the port-group's socket buffer size (socket-buf-size in /clusters/cluster-#/cluster-connectivity/option-sets/optionset-com-#/). The default as of GeoSynchrony 5.1 is 1MB. The optimal value for this is the network's delay-bandwidth product which is the latency or delay of the network multiplied by the available bandwidth, which is the amount of data required to be outstanding to fully utilize the network.

Network's delay-bandwidth product = latency or delay of the network “X” available bandwidth For VPLEX Geo, the Queue Depth helps VPLEX handle bursty traffic along with write-pacing. The default value is 6 and it may be set up to 64. This can be tuned before or after RAPIDPath is implemented.

Figure-12 illustrates a simple example of a deployment of RAPIDPath in a VPLEX environment:

Figure 12 - Sample RAPIDPath Deployment with VPLEX – Multihomed Multipathing

As shown in Figure 12 above, this environment takes advantage of the RAPIDPath Multihomed Multipathing feature by adding redundancy and throughput for each service provider. In order to configure the Multihomed Multipathing feature in RAPIDPath you must have a router that supports GRE Tunnel endpoints and Policy Based Routing (PBR) for GRE Tunnels.

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Deploying RAPIDPath with VPLEX Metro-IP and Geo An overview of the process for implementing VPLEX with RAPIDPath:

• RAPIDPath Configuration o Configure DATA Port o Establish the peers o Configure Multihomed Multipathing (if appropriate)

Configure edge/WAN router portion of GRE Tunnels Configure RAPIDPath portion of GRE Tunnels

• VPLEX Configuration o Verify VPLEX Clusters’ WAN Com connectivity and their health o Determine the VPLEX performance parameters adjustments necessary

• Insert RAPIDPath into the each port group network path o Re-verify WAN Com connectivity for port group 0 o Take port group 0 offline o Make performance adjustments to port group 0 o Physically insert RAPIDPath into the network path o Return port group 0 online o Verify WAN Com connectivity re-establishes for port group 0 o Disable RAPIDPath bypass mode o Repeat for port group 1

To reiterate: Before deploying RAPIDPath into the VPLEX environment, steps should be taken to be sure the VPLEX clusters are healthy and conform to the practices outlined in the VPLEX Implementation and Planning Best Practices Tech Note.

Figure 13 - Typical single engine VPLEX installation prior to inserting RAPIDPath inline

To connect RAPIDPath to an existing VPLEX environment, you must bring the IP WAN COM module of VPLEX into the maintenance mode. Typically, there are two links between two VPLEX entities, which are called port-groups. You must only install RAPIDPath on one port-group at a time. The installation procedure of RAPIDPath on one port-group must not impact the performance of the other port-group. Before using RAPIDPath in a VPLEX environment, make sure that you set the MTU and the Socket Buffers according to your anticipated workloads.

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First we will take Port Group 0 Offline, Insert RAPIDPath Node-1, and then Resume Port Group 0. As shown in Figure 14.

Figure 14 - Inserting RAPIDPath Appliance for Port Group 0

Second, we will take Port Group 1 Offline, Insert RAPIDPath Node-3, and then resume Port Group 1

Figure 15 - Inserting RAPIDPath Appliance for Port Group 1

VPLEX Metro-IP and VPLEX Geo clusters will utilize a total (4) RAPIDPath Nodes per VPLEX Cluster with 2 nodes located at each data center site. Note: Each RAPIDPath node should be placed into bypass mode until all requirements have been met as described in the Product and Installation Guides.

Conclusion RAPIDPath will enhance your VPLEX environments by optimizing TCP and UDP (UDT) based network traffic between data centers using three main mechanisms: Intelligent Transport, TCP Optimization, and Multihomed Multipathing. Using the RAPIDPath appliance allows customers to make all WAN links active and intelligently manages traffic across all network paths. This allows customers to fully utilize all bandwidth in multiple link configurations and provides continuous availability. In the event of a link failure, RAPIDPath intelligently routes traffic over the other link without breaking network connectivity or requiring a WAN failover. Additionally, RAPIDPath manages multiple IP flows across any single physical connection, improving throughput up to 40 percent on degraded network connections

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Appendix-A: RAPIDPath Related Terminology and Definitions Bypass Mode

Bypass Mode is a safety measure designed to prevent RAPIDPath from cutting off traffic between the LAN and the WAN in the event of a failure. If the RAPIDPath software fails, the LAN and WAN plugs behave as though they are hard-wired together. It is possible to place a RAPIDPath appliance in bypass mode manually.

Data Port

All of the data traffic that the RAPIDPath optimizes travels through this port. The Data port is a bridged interface that corresponds to the physical LAN and WAN ports. The RAPIDPath software treats the Data port like a single physical interface, deciding dynamically whether to use the LAN or WAN interface. You do not normally need to refer to the LAN and WAN interfaces separately when configuring the RAPIDPath.

Local Network

RAPIDPath optimizes the data from the computers and appliances that belong to a Local Area Network (LAN). Each network segment targeted for optimization is referred to as a Local Network. The local network can be a single IP Address or a range of IP Addresses that falls under a network mask.

Maximum Transmission Unit (MTU) The largest frame size that can be transmitted over the network. (source: PCMag.com encyclopedia)

Peer A RAPIDPath appliance must be connected to another RAPIDPath appliance to optimize the data traffic. This RAPIDPath appliance located on the remote site is referred to as the local RAPIDPath appliance’s peer.

Peer Network To process the optimized data, RAPIDPath must have the network information of the systems on the local network segment of the peer RAPIDPath. To configure the peer network, make sure that you have the IP Address of the each target system in the peer network. The peer network can be a single IP Address or a range of IP Addresses that falls under a network mask.

Spanning Tree Protocol (STP)

Spanning Tree Protocol (STP) is another safety measure used to protect your Layer 2 network environment from bridge loops that may potentially cause one or more switch ports to be disabled.

User Datagram Protocol (UDP)

Minimum IP protocol that has no handshake and relies on the application layer to ensure reliable communications. (no guarantee of delivery)

UDP based Data Transport (UDT) Data Transfer protocol designed for transporting large amounts of data without some of the protocol constraints of TCP

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EMC CONFIDENTIAL

Appendix-B: RAPIDPath and VPLEX Firewall/Port Requirements The following firewall / ACL ports must be open for input: Port

Protocol and description

Effect if closed

22/23 SSH and communications (TCP)

•No log collection •No remote connection to CLI

25 Outgoing mail (SMTP) email alerts, if configured (TCP)

•No email alerts sent.

53 DNS (TCP, UDP) •No name resolution of remote servers; e-mail alerts, system reports

80 HTTP; web server for management (TCP)

•No GUI •RAPIDPath is designed to be used with the GUI

123 NTP (TCP, UDP) •Needed to synchronize with time server.

161 SNMP (TCP, UDP) •SNMP notification

162 SNMP (TCP, UDP) •SNMP notification

443 HTTPS; for management (TCP) •No RAPIDPath or VPLEX GUI (also VPLEX API) •No replication

514 Syslog (TCP, UDP) •System logs not available

7115 For VMware Site Recovery Manager communication (TCP)

•No vCenter Server information or commands available

16000 PAIT (UDP) •RAPIDPath Intelligent Transport VPLEX firewall requirements (in addition to those listed above: 23,25,161,162,443) 22/23 500

SSH ISAKMP

• Management Server/VPLEX CLI • Metro VPN

4500 IPSec NAT traversal • Metro VPN

5400 - 5413

ESRS •No deployment tools

Appendix-C: Reference Documentation • EMC VPLEX page on EMC.com • RAPIDPath System Administrators Guide (support.emc.com) • RAPIDPath Installation and Configuration Guide (support.emc.com) • RAPIDPath VPLEX Integration Guide (support.emc.com) • VPLEX Implementation and Planning Best Practices (support.emc.com)

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