How to Build a MAN Last Update 2007.05.27 1.0.0 Copyright 2000-2007 Kenenth M. Chipps PhD 1.

How to Build a MAN

Last Update 2007.05.27

1.0.0

Copyright 2000-2007 Kenenth M. Chipps PhD www.chipps.com

1

Objectives of This Section

• Learn– What a MAN looks like in general

Copyright 2000-2007 Kenenth M. Chipps PhD www.chipps.com 2

What is a MAN

• A MAN connects sites that are too far to walk to

• But you can drive there in a short while• It uses some of the same technologies a

WAN uses• It may require a WAN service provider to

be used


What is a MAN

• When we discussed the CAN just previous to this presentation nothing was said about right of way issues

• That is because most CANs stay on your property

• In some cases a CAN must cross a street but in general it stays in one location

• A MAN on the other hand by definition must go through somebody else’s backyard


Layouts for MANs

• A MAN is usually in one of two forms– Point-to-Point– Ring

• Although a star pattern as seen in a LAN and CAN is in essence just a bunch of point-to-point links, a star is not a normal layout for a MAN


Layers in MANs

• An ongoing argument concerning MANs is what to do about the data link layer

• As seen in the table a few slides down, the lower part of the physical layer is pretty well defined

• It consists of fiber optic cable carrying light divided into wavelengths, with each wavelength or lambda carrying a signal


Layers in MANs

• This is called DWDM – Dense Wave Division Multiplexing

• The next layer up is where the argument starts


Layers in MANs

• Right now everyone uses SONET for the most part

• The argument is - is this the best way to send data over long distances

• Some say no, just put IP directly on the fiber

• But others say you must still have a layer 2, since IP is layer 3


Layers in MANs

• The argument then is what should this layer 2 be or is it even needed

• Options include– IP directly on fiber in some manner, such as

PPP– MPLS used to organize IP– 10 GB Ethernet– POS – Packet Over SONET– ATM


Layers in MANs

Traditional Ring Point to Point Discussed

IP

ATM POS

SONET SONET IP

DWDM DWDM DWDM

Fiber Fiber Fiber


Point-to-Point MAN

• The simplest MAN just connects two locations


Building A Building B

Cable

Point-to-Point MAN Made

• To do this fiber optic cable is laid underground from Building A to Building B

• At each end point a piece of equipment is used to connect the fiber


Point-to-Point MAN

• Loose Tube SM – Single Mode Fiber Optic Cable


Point-to-Point MAN

• As a MAN link normally carries a lot of traffic, at each end point a fairly powerful box is required

• Equipment of this sort may also require a specialized external power supply, which is shown at the bottom of the rack

• A rack is also a good place to terminate the fiber that connects the two locations, this is the job of the patch panel at the top of the rack


Point-to-Point MAN


Point-to-Point MAN

• The Relay Rack


Point-to-Point MAN

• Fiber Optic Cable Patch Panel


Point-to-Point MAN

• Fiber Optic Cable Patch Panel which mounts in the cabinet in the two oval openings


Point-to-Point MAN

• SM Fiber Optic Cable SC Connector which mounts to the back side of the patch panel


Point-to-Point MAN

• Cisco 12000 Series Router/Switch with POS – Packet over SONET module


Point-to-Point MAN

• Power Supply


Send Data Point-to-Point

• The reason for the big, expensive Cisco Router/Switch is that we will be sending the data over a long distance, in this example say 30 kilometers

• This distance will require we use POS – Packet Over SONET

• Recall the layers discussed above


Send Data Point-to-Point

• When just connecting two points there is no need for the overhead ATM introduces, just form up the IP packets and deliver them to SONET at the physical layer


Ring MAN


Building A

Building B

Building C

Ring MAN

• Fiber optic cable is laid underground from point to point to point around a ring with a diameter of say 10 to 50 kilometers

• At each point a piece of equipment is used to connect to the fiber

• This equipment adds signals or removes signals, just like an on or off ramp for a freeway


Ring MAN

• A freeway loop around a city like 635 around Dallas or 820 around Fort Worth is a perfect example of what a Ring MAN looks like and the size they often are


Ring MAN


Loop 820 aroundFort Worth

Why Use a Ring Shape

• The main reason for the ring and the expensive and bother associated with it and the access line methods used to send data over it is the ability of this combination to fix itself

• For example, notice that the ring above has two fiber optic cables shown

• This allows one set of fibers to fail, with the other taking over all of the load



• Further, both fibers can be cut and the ring will wrap to keep working




Building A

Building B

Building C

Equipment for a Ring MAN

• The equipment used for a ring shaped MAN is pretty much the same as that for a point-to-point MAN

• The major difference is the type of box at each point

• Rather than a Layer 3 Switch with a POS module as shown above, each on and off ramp or location on the ring MAN will use a device called an ADM


Equipment for a Ring MAN

• ADM - Add/Drop Multiplexor


Send Data on a Ring MAN

• ATM on top of SONET as seen in the diagram a few slides back is the preferred method right now for sending data for a MAN as large as the one described here

• The main reason for this is the ability of this combination to produce resiliency and ease OA&M – Operations, Administration, and Maintenance



• As you should recall from the access line presentations SONET has excellent fault tolerance

• ATM makes excellent use of all available bandwidth



• With the amount of traffic sent over a MAN of this size it makes sense to put up with the complexity of SONET and ATM in order to get back their administrative and fault tolerance capabilities


Other Issues Peculiar to a MAN

• As described above the equipment and method used to send the data over the medium length distances that constitute a MAN are no big deal

• The problem is ground – right of way – you can use to bury the fiber optic cable required to connect the sites

• This is the tricky part of making a MAN


Review

• What is a MAN


How to Build a MAN Last Update 2007.05.27 1.0.0 Copyright 2000-2007 Kenenth M. Chipps PhD 1.

Documents

Transcript of How to Build a MAN Last Update 2007.05.27 1.0.0 Copyright 2000-2007 Kenenth M. Chipps PhD 1.