NOTE: Any update that contains the AS path number 0 is valid.The AS path is shown in the following example. The origin attribute is shown following the AS path information (shown in bold).Example of Viewing AS PathsDell#show ip bgp pathsTotal 30655 PathsAddress Hash Refcount Metric Path0x4014154 0 3 18508 701 3549 19421 i0x4013914 0 3 18508 701 7018 14990 i0x5166d6c 0 3 18508 209 4637 1221 9249 9249 i0x5e62df4 0 2 18508 701 17302 i0x3a1814c 0 26 18508 209 22291 i0x567ea9c 0 75 18508 209 3356 2529 i0x6cc1294 0 2 18508 209 1239 19265 i0x6cc18d4 0 1 18508 701 2914 4713 17935 i0x5982e44 0 162 18508 209 i0x67d4a14 0 2 18508 701 19878 ?0x559972c 0 31 18508 209 18756 i0x59cd3b4 0 2 18508 209 7018 15227 i0x7128114 0 10 18508 209 3356 13845 i0x536a914 0 3 18508 209 701 6347 7781 i0x2ffe884 0 1 18508 701 3561 9116 21350 iNext HopThe next hop is the IP address used to reach the advertising router.For EBGP neighbors, the next-hop address is the IP address of the connection between the neighbors. For IBGP, the EBGP next-hop address is carried into the local AS. A next hop attribute is set when a BGP speaker advertises itself to another BGP speakeroutside its local AS and when advertising routes within an AS. The next hop attribute also serves as a way to direct traffic to anotherBGP speaker, rather than waiting for a speaker to advertise. When a next-hop BGP neighbor is unreachable, then the connection tothat BGP neighbor goes down after hold down timer expiry. The connection flap can also be obtained immediately with Falloverenabled. BGP routes that contain the next-hop as the neighbor address are not sent to the neighbor. You can enable this featureusing the neighbor sender-side-loopdetect command.NOTE: For EBGP neighbors, the next-hop address corresponding to a BGP route is not resolved if the next-hop addressis not the same as the neighbor IP address.NOTE: The connection between a router and its next-hop BGP neighbor terminates immediately only if the router hasreceived routes from the BGP neighbor in the past.Multiprotocol BGPMultiprotocol extensions for BGP (MBGP) is defined in IETF RFC 2858. MBGP allows different types of address families to bedistributed in parallel.MBGP allows information about the topology of the IP multicast-capable routers to be exchanged separately from the topology ofnormal IPv4 and IPv6 unicast routers. It allows a multicast routing topology different from the unicast routing topology.MBGP uses either an IPv4 address configured on the interface (which is used to establish the IPv6 session) or a stable IPv4 addressthat is available in the box as the next-hop address. As a result, while advertising an IPv6 network, exchange of IPv4 routes does notlead to martian next-hop message logs.NOTE: It is possible to configure BGP peers that exchange both unicast and multicast network layer reachabilityinformation (NLRI), but you cannot connect multiprotocol BGP with BGP. Therefore, you cannot redistributemultiprotocol BGP routes into BGP.156 Border Gateway Protocol IPv4 (BGPv4)
