The benefits of route dampening are noticed inside as well as outside an autonomous system. When BGP is redistributed (injected) into an IGP, it is important that BGP instability does not affect internal routing in such a way as to cause a meltdown inside the AS. This is where route dampening can be useful. Routes that are flapping will be suppressed and prevented from being injected into the AS until they show some degree of stability. Figure 10-2 compares the effects of EBG..
Building Adjacency Information: ARP and Inverse ARP
The CEF adjacency table entries list an outgoing interface and a Layer 2 and Layer 3 address reachable via that interface. The table also includes the entire data link header that should be used to reach that next-hop (adjacent) device. The CEF adjacency table must be built based on the IP routing table, plus other sources. The IP routing table entries include the outgoing interfaces to use and the next-hop device’s IP address. To complete the adjacency table entry for tha..
In the first section of this appendix you saw the overall MPLS architecture as well as the underlying concepts. This chapter focuses on one particular application: unicast destination-based IP routing in a pure router environment (also called Frame-mode MPLS because the labeled packets are exchanged as frames on Layer 2). This section first focuses on the MPLS data plane, assuming that the labels were somehow agreed upon between the routers. The next section explains the exa..
You can use the optional size attribute with the logging buffered configuration command to change the size of your router's internal log buffer: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#logging buffered 16000 Router(config)#end Router# Be careful, though, because adjusting the size of the router's logging buffer wipes out all of the current contents of the buffer. The typical default size of a router's log..
The root path cost for each active port of a switch is determined by the cumulative cost as a BPDU travels along. As a switch receives a BPDU, the port cost of the receiving port is added to the root path cost in the BPDU. The port or port path cost is inversely proportional to the port’s bandwidth. If desired, a port’s cost can be modified from the default value. Note: Before modifying a switch port’s path cost, you should always calculate the root path costs of other..
