Physical Versus Logical Connections
External BGP neighbors have a restriction in that they must be physically connected, adjacent to one another. BGP drops any UPDATE message from its external BGP peer if the peer is not physically connected, unless otherwise specified. However, some situations arise in which external neighbors cannot be on the same physical segment. Such neighbors are logically connected (multiple IP hops away) but not physically connected. An example would be running BGP between external neig..
Neighborship and Reliable Incremental Updates
EIGRP produces reliable updates by identifying its packets using IP protocol 88. Reliable, in a networking context, means that the receiver acknowledges that the transmission was received and understood. EIGRP only repeats itself if an advertisement is lost, so EIGRP is less "chatty" than other protocols. EIGRP uses the following five types of packets to communicate. These packets are directly encapsulated by IP. • Hello— Identifies neighbors. Hellos are sent as periodi..
Appreciating what QoS tools and methods do to packets in a network is fundamental to appreciating the effect of individual QoS tools discussed in later chapters, and ultimately understanding the network designs and methods that constitute the material in this book. End-to-End QoS Regardless of how it is measured, QoS is a vital element in any converged network. To ensure the highest level of quality, however, QoS must be implemented across all areas of the network. QoS is d..
Use the logging rate-limit configuration command to limit the number of syslog packets sent to your server: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#logging host 172.25.1.1 Router(config)#logging rate-limit 30 except warnings Router(config)#end Router# To rate limit the number of log messages sent to the console port, use the following command: Router#configure terminal Enter configuration commands, one per..
Dynamically Allocating Client IP Addresses via DHCP
The following set of configuration commands allows the router to dynamically allocate IP addresses to client workstations: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#service dhcp Router1(config)#ip dhcp pool 172.25.1.0/24 Router1(dhcp-config)#network 172.25.1.0 255.255.255.0 Router1(dhcp-config)#default-router 172.25.1.1 Router1(dhcp-config)#exit Router1(config)#ip dhcp excluded-address 172.25.1.1 172..
