Caveats Regarding OSPF Network Types over NBMA Networks
When configuring OSPF over Frame Relay, the OSPF network type concept can become a bit troublesome. In fact, many CCIE Routing and Switching lab preparation texts and lab books focus on the variety of combinations of OSPF network types used with Frame Relay for various interfaces/subinterfaces. The following list contains many of the key items you should check when looking at an OSPF configuration over Frame Relay, when the OSPF network types used on the various routers do no..
LDP Control-Plane and Forwarding-Plane Components
The state of an LSP that is established through LDP can be divided into two components: the LDP state (which is maintained in the control plane), and the MPLS forwarding state (which is maintained in the forwarding plane). The exact format of the LDP state or the MPLS forwarding state of an LSP in an LSR depends on whether the LSR is ingress, egress, or transit for that LSP. For example, LSP ingress LSR uses a FEC-to-NHLFE (FTN) entry to map the associated FEC to one or more..
Monitoring and Troubleshooting CBWFQ for Frame Relay
The show policy-map privileged EXEC command can be used to display the configurations of all classes comprising the specified service policy map or all classes for all existing policy maps. A sample output of the show policy-map command is shown in Example 18-4. Example 18-4. Output of show policy-map Command at R1 R1#show policy-map Policy Map CBWFQ Class premium Weighted Fair Queueing &n..
Recall that the traditional STP offers the PortFast feature, in which switch ports are allowed to immediately enter the Forwarding state as soon as the link comes up. Normally, PortFast provides quick network access to end-user devices, where bridging loops never are expected to form. Even while PortFast is enabled on a port, STP still is running and can detect a bridging loop. However, a loop can be detected only in a finite amount of time— the length of time require..
Adjusting Local Preference Values
When BGP routers within an AS exchange information about a particular route using iBGP, they include the Local Preference value. All of the routers in the AS are then able to use this value to decide how to weight this route versus other BGP routes to the same destination. BGP consults the Local Preference value early in the route selection process, before even the AS Path attribute. So this provides an extremely useful and flexible way of forcing particular routes to use par..
