How to Build a MAN Last Update Copyright Kenenth M. Chipps PhD 1

Objectives of This Section Learn –What a MAN looks like in general Copyright Kenenth M. Chipps PhD 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 Copyright Kenenth M. Chipps PhD 3

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 Copyright Kenenth M. Chipps PhD 4

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 Copyright Kenenth M. Chipps PhD 5

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 Copyright Kenenth M. Chipps PhD 6

Layers in MANs This is called DWDM – Dense Wave Division Multiplexing The next layer up is where the argument starts Copyright Kenenth M. Chipps PhD 7

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 Copyright Kenenth M. Chipps PhD 8

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 Copyright Kenenth M. Chipps PhD 9

Layers in MANs Traditional RingPoint to PointDiscussed IP ATMPOS SONET IP DWDM Fiber Copyright Kenenth M. Chipps PhD 10

Point-to-Point MAN The simplest MAN just connects two locations Copyright Kenenth M. Chipps PhD 11 Building ABuilding 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 Copyright Kenenth M. Chipps PhD 12

Point-to-Point MAN Loose Tube SM – Single Mode Fiber Optic Cable Copyright Kenenth M. Chipps PhD 13

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 Copyright Kenenth M. Chipps PhD 14

Point-to-Point MAN Copyright Kenenth M. Chipps PhD 15

Point-to-Point MAN The Relay Rack Copyright Kenenth M. Chipps PhD 16

Point-to-Point MAN Fiber Optic Cable Patch Panel Copyright Kenenth M. Chipps PhD 17

Point-to-Point MAN Fiber Optic Cable Patch Panel which mounts in the cabinet in the two oval openings Copyright Kenenth M. Chipps PhD 18

Point-to-Point MAN SM Fiber Optic Cable SC Connector which mounts to the back side of the patch panel Copyright Kenenth M. Chipps PhD 19

Point-to-Point MAN Cisco Series Router/Switch with POS – Packet over SONET module Copyright Kenenth M. Chipps PhD 20

Point-to-Point MAN Power Supply Copyright Kenenth M. Chipps PhD 21

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 Copyright Kenenth M. Chipps PhD 22

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 Copyright Kenenth M. Chipps PhD 23

Ring MAN Copyright Kenenth M. Chipps PhD 24 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 Copyright Kenenth M. Chipps PhD 25

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 Copyright Kenenth M. Chipps PhD 26

Ring MAN Copyright Kenenth M. Chipps PhD 27 Loop 820 around Fort 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 Copyright Kenenth M. Chipps PhD 28

Why Use a Ring Shape Further, both fibers can be cut and the ring will wrap to keep working Copyright Kenenth M. Chipps PhD 29

Why Use a Ring Shape Copyright Kenenth M. Chipps PhD 30 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 Copyright Kenenth M. Chipps PhD 31

Equipment for a Ring MAN ADM - Add/Drop Multiplexor Copyright Kenenth M. Chipps PhD 32

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 Copyright Kenenth M. Chipps PhD 33

Send Data on a Ring MAN As you should recall from the access line presentations SONET has excellent fault tolerance ATM makes excellent use of all available bandwidth Copyright Kenenth M. Chipps PhD 34

Send Data on a Ring MAN 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 Copyright Kenenth M. Chipps PhD 35

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 Copyright Kenenth M. Chipps PhD 36

Review What is a MAN Copyright Kenenth M. Chipps PhD 37