Requesting, Getting, and Acknowledging LSAs
Once all LSA headers have been exchanged using DD packets, each neighboring router has a list of LSAs known by the neighbor. Using that knowledge, a router needs to request a full copy of each LSA that is missing from its LSDB. To know if a neighbor has a more recent copy of a particular LSA, a router looks at the sequence number of the LSA in its LSDB and compares it to the sequence number of that same LSA learned from the DD packet. Each LSA’s sequence number is increment..
BGP Configuration Stencil for Large Networks
The following basic configuration summarizes the commentary of this section. It is not necessary to include the complete configuration as part of your default BGP configuration. You should study this section to see what is suitable for your environment: interface loopback 0 ip address 1.0.0.1 255.255.255.255 router bgp 100 no synchronization bgp router-id 1.0.0.1 no bgp fast-external-fallover bgp log-neighbor-changes ..
Four-Step STP Decision Sequence
When creating a loop-free logical topology, Spanning Tree always uses the same four-step decision sequence: • Lowest Root BID • Lowest Path Cost to Root Bridge • Lowest Sender BID • Lowest Port ID Bridges pass Spanning Tree information between themselves using special frames known as bridge protocol data units (BPDUs). A bridge uses this four-step decision sequence to save a copy of the best BPD..
The remaining sections of this chapter focus on the Frame Relay PIPQ feature. The Frame Relay PIPQ feature works by providing a PQ scheme at the interface level. Similar to the generic PQ feature enabled at the interface level for nonserial interfaces or other encapsulation types, the Frame Relay PIPQ feature provides four queues of ascending levels of priority: low, normal, medium, and high. NOTE The Frame Relay PIPQ feature is supported in Cisco IOS Release 12.1(1)T and l..
Configuring a Basic MPLS PE Router
To configure a PE router, you must set up connections to the MPLS core as well as to one or more customer networks. Further, to distribute customer VRF routing information to other PE routers, you must configure MP-BGP: Router-PE1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router-PE1(config)#ip cef Router-PE1(config)#mpls ip Router-PE1(config)#interface Serial0/0 Router-PE1(config-if)#description Connection to Router-P1 Router..
