Figure 92 POP with 11 or Fewer CRs

Figure 9-3. POP with More Than 11 CRs

The entire network consists of 28 WRs, 12 DRs, and 128 CRs—a total of 168 routers. It's not the world's largest network, but it's certainly large enough to demonstrate the points made in this chapter.

CR uplinks (to either WR or DR, depending on POP topology) are OC-3 POS links. DR uplinks to WRs (where applicable) are OC-48s.

Because you'll need these numbers later for a case study, Table 9-1 provides the exact count of how many WRs, DRs, and CRs are in each POP.

Table 9-1. WRs, DRs, and CRs in Each POP

POP Location

WRs

DRs

CRs

Seattle

2

3

14

San Jose

2

0

11

San Diego

2

0

8

Denver

2

0

3

Dallas

2

0

5

Houston

2

0

6

St. Louis

2

0

6

Chicago

2

0

7

Atlanta

2

0

9

Raleigh

2

3

12

D.C.

2

3

15

New York

2

3

20

Boston

2

0

8

Miami

2

0

4

All routers are at the same IS-IS level; they're all Level 2 neighbors. However, almost anything you do with IS-IS is possible with OSPF, so if you'd rather read about an OSPF network, just assume that the network is a single OSPF Area 0.

When discussing WR full mesh, it is only necessary for the WRs to be at the same level or area. The POPs can be in separate areas if that's how you'd rather picture them.

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