OSPF design calls for grouping links into contiguous areas. Routers that connect to links in different areas are Area Border Routers (ABRs). ABRs must connect to area 0, the backbone area, and one or more other areas as well. Autonomous System Boundary Routers (ASBRs) inject routes external to OSPF into the OSPF domain, having learned those routes from wide-ranging sources from the Border Gateway Protocol (BGP) on down to simple redistribution of static routes. Figure 10-5 s..
Multicast Open Shortest Path First
MOSPF is defined in RFC 1584, “Multicast Extensions to OSPF,” which is an extension to the OSPFv2 unicast routing protocol. The basic operation of MOSPF is described here: ■ MOSPF uses the group membership LSA, Type 6, which it floods throughout the originating router’s area. As with unicast OSPF, all MOSPF routers in an area must have identical linkstate databases so that every MOSPF router in an area can calculate the same SPT. ■ The SPT is calculated “on-dema..
The development of routers can be characterized through three generations. The first generation consists of a single CPU controlling relatively unsophisticated line cards through a general- purpose shared I/O bus. Packet queues between line cards are maintained in central or shared memory by the CPU, which coordinates all packet forwarding. In the worst case, packets may traverse the I/O bus twice to complete the forwarding process. A second-generation switch su..
ISAKMP/IKE Phase 2 Data Connections
This part of the chapter will discuss the components you need to configure for the Phase 2 data connections in an IPsec L2L session for your PIX/ASA security appliance. This includes specifying what traffic to protect and how it should be protected. If you've configured L2L sessions on routers, the process and commands described here will be nothing new to you. Note Please note that even though Cisco has added many IPsec enhancements in 7.0, the PIX/ASA still lags behind ro..
Each Cisco switch participating in VTP advertises VLANs (only VLANs 1 to 1005), revision numbers, and VLAN parameters on its trunk ports to notify other switches in the management domain. VTP advertisements are sent as multicast frames. The switch intercepts frames sent to the VTP multicast address and processes them with its supervisory processor. VTP frames are forwarded out trunk links as a special case.Because all switches in a management domain learn of new VLAN configur..
