Building BGP Neighbor Relationships

BGP neighbors form a TCP connection with each neighbor, sending BGP messages over the connections—culminating in BGP Update messages that contain the routing information. Each router explicitly configures its neighbors’ IP addresses, using these definitions to tell a router with which IP addresses to attempt a TCP connection. Also, if a router receives a TCP connection request (to BGP port 179) from a source IP address that is not configured as a BGP neighbor, the router ..

RTS/CTS and Fragmentation Summary

Table 22-3 summarizes some of the benefits and drawbacks of both RTS/CTS and fragmentation when trying to improve throughput in a wireless network. Table 22-3 Improving Throughput Using RTS/CTS and Fragmentation    

Overview of Communications History

Networks are now a core component of our business and personal lives. Today, businesses that may hobble along with the loss of telephone service can be rendered nonfunctional by the loss of their data network infrastructure. Understandably, corporations spend a great deal of time and money nursing this critical resource. How and why did this dependency occur? Simply because networks provide a means to amplify all the historical communication mechanisms. Nearly 50,000 ye..

Using Named and Reflexive Access-Lists

A basic named ACL is similar to the numbered ACLs that we discussed earlier in this chapter. They can work like either Standard or Extended IP ACLs: Router1#configure terminalEnter configuration commands, one per line.  End with CNTL/Z.Router1(config)#ip access-list standard STANDARD-ACLRouter1(config-std-nacl)#remark This is a standard ACLRouter1(config-std-nacl)#permit any logRouter1(config-std-nacl)#exitRouter1(config)#ip access-list extended EXTENDED-ACLRouter1(conf..

hoosing Where to Summarize Routes

EIGRP supports route summarization at any router, unlike OSPF, which requires that summarization be performed only at area border routers (ABR) or autonomous system border routers (ASBR). EIGRP’s flexibility helps when designing the internetwork, but it also poses some questions as to where to summarize EIGRP routes. In some cases, the options are relatively obvious. For example, consider the 10.17.32.0/19 address block in manufacturing in Figure 1-1. The manufacturing divi..