BGP Policies Conflicting with the Internal Default

Anytime internal routers are following defaults to reach routes unknown to the AS, you should be careful not to create routing loops. A routing loop occurs when router X follows a default toward router Y, which in turn uses router X to reach the destination. The traffic will end up bouncing between routers X and Y. The default route 0/0 is injected differently from BGP into the IGP, depending on what IGP you are using. Different scenarios will be considered, utilizing OSPF, R..

Common Problems with Adjacencies

Many OSPF problems stem from adjacency problems that propagate throughout the network. Problems are often traced back to neighbor discrepancies. The following guidelines are helpful in these situations.  If a router configured for OSPF routing is not seeing an OSPF neighbor on an attached network, do the following:  • Make sure that both routers are configured with the same IP mask, MTU, interface Hello timer, OSPF Hello interval, and OSPF dead interval.  ..

Sending Log Messages to Your Screen

Use the terminal monitor command to enable the displaying of log messages to your VTY: Router#terminal monitor Router# To disable logging to your VTY session, use the following command: Router#terminal no monitor Router# Routers forward all logging messages to their console ports by default, but not to their VTY lines. When you are troubleshooting a network problem on a remote router, it is often quite useful to instruct the router to send log messages to your VTY so that ..

Configuring Frame Relay FRF.9 Payload Compression

The Cisco packet-by-packet payload compression scheme for Frame Relay is a proprietary compression algorithm that does not work too well in a multivendor environment. As such, a need for a new compression algorithm that is multivendor compatible arises. The Frame Relay FRF.9 payload compression, based on the implementation agreement for data compression over Frame Relay (FRF.9) approved by the Frame Relay Forum, provides a higher compression performance compared with the pac..

Creating a Default Route in OSPF

To propagate a default route with OSPF, use the default-information originate configuration command: Router1#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router1(config)#ip route 0.0.0.0 0.0.0.0 172.25.1.1 Router1(config)#router ospf 55 Router1(config-router)#default-information originate metric 30 metric-type 1 Router1(config-router)#exit Router1(config)#end Router1# Unlike RIP and EIGRP, you cannot create a default route in OSPF b..