Forcing Ingress Multicast Replication Mode (Optional)
The MVPN feature supports only ingress multicast replication mode. If the switch is currently configured for egress replication, it is forced into ingress replication when the first MVRF is configured. This change in replication mode automatically purges all forwarding entries in the hardware, temporarily forcing the switch into software switching until the table entries can be rebuilt. To avoid disrupting customer traffic, we recommend verifying that the switch is already i..
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..
Figure 14-13 shows the format of RSVP messages, which consist of a header containing seven defined fields and one reserved field, followed by a main body containing a series of RSVP objects. Figure 14-13. RSVP Message s Each message begins with a 4-bit RSVP version number: the current version is 2. This is followed by a 4-bit flag field, which is currently unused. The type field indicates the message type: A 16-bit standard TCP/UDP checksum is used over the..
Using Spanning Tree in Real-World Networks
Look at Figure 6-20 for a more complex topology, and see how all this STP detail adds up in the real world. Figure 6-20. A Complex Network with All Links Shown Figure 6-20 illustrates a network of seven switches connected in a highly redundant (that is, looped) configuration. Link costs are indicated—all are Fast Ethernet (cost of 19) except for the vertical link on the far left that is 10BaseT (cost of 100). Assuming that Cat-4 wins the Root War, F..
Troubleshooting VLANs and Trunks
Remember that a VLAN is nothing more than a logical network segment that can be spread across many switches. If a PC in one location cannot communicate with a PC in another location, where both are assigned to the same IP subnet, make sure that both of their switch ports are configured for the same VLAN. If they are, examine the path between the two. Is the VLAN carried continuously along the path? If there are trunks along the way, is the VLAN being carried across the trunks..
