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..
A careful reader might start asking an interesting question: If there is no one-to-one mapping between VPN and VRF, how does the router know which routes need to be inserted into which VRF? This dilemma is solved by the introduction of another concept in the MPLS/VPN architecture: the route target. Every VPN route is tagged with one or more route targets when it is exported from a VRF (to be offered to other VRFs). You can also associate a set of route targets with a VRF, and..
Configuring IPX Routing Commands
As mentioned earlier in this chapter, you enable IPX routing with the global configuration command ipx routing. After IPX routing is enabled, the router builds the routing table used for routing. By default, when an IPX address is configured on a LAN or WAN interface and that interface is placed in an operational state, the IPX network address for that interface is placed in the routing table. All operational interfaces connected to the router are placed in the routing table...
Introduction to Link-State Protocols
In the field of networking, we compare link-state protocols to jigsaw puzzles—each router is one piece of the puzzle. When the routers are joined, they form the complete picture. Every router within an area holds a piece of the puzzle. All routers within the same area have identical information about all the links and routers. Therefore, all the routers in the same area know the identity of the router that originated the information about its link and its neighbors. &n..
LDP GR Mechanism for Downstream On-Demand Mode
LDP GR Mechanism for Downstream On-Demand Mode The previous section described LDP GR mechanism for the downstream unsolicited label distribution mode.[7] This section describes the LDP GR mechanism for downstream on-demand label distribution by drawing on the concepts of the previous section. To avoid repetition of information already described in the previous section, the following discussion first summarizes LDP GR procedures that are common to both modes. It then describe..
