IBGP provides routers inside the AS with the knowledge to reach routers external to the AS. EBGP routers exchange information with other
EBGP routers as well as IBGP routers to maintain connectivity and accessibility.
Figure 17. Internal BGP
BGP version 4 (BGPv4) supports classless interdomain routing and aggregate routes and AS paths. BGP is a path vector protocol — a
computer network in which BGP maintains the path that updated information takes as it diffuses through the network. Updates traveling
through the network and returning to the same node are easily detected and discarded.
BGP does not use a traditional interior gateway protocol (IGP) matrix, but makes routing decisions based on path, network policies, and/or
rulesets. Unlike most protocols, BGP uses TCP as its transport protocol.
Since each BGP router talking to another router is a session, a BGP network needs to be in “full mesh.” This is a topology that has every
router directly connected to every other router. Each BGP router within an AS must have iBGP sessions with all other BGP routers in the
AS. For example, a BGP network within an AS needs to be in “full mesh.” As seen in the illustration below, four routers connected in a full
mesh have three peers each, six routers have five peers each, and eight routers in full mesh have seven peers each.
168
Border Gateway Protocol IPv4 (BGPv4)
Summary of Contents for S3048-ON
Page 1: ...Dell Configuration Guide for the S3048 ON System 9 11 2 5 ...
Page 137: ...0 Gi 1 1 Gi 1 2 rx Flow N A N A 0 0 No N A N A yes Access Control Lists ACLs 137 ...
Page 142: ...Figure 10 BFD Three Way Handshake State Changes 142 Bidirectional Forwarding Detection BFD ...
Page 241: ...Dell Control Plane Policing CoPP 241 ...
Page 287: ... RPM Synchronization GARP VLAN Registration Protocol GVRP 287 ...
Page 428: ...Figure 53 Inspecting the LAG Configuration 428 Link Aggregation Control Protocol LACP ...
Page 477: ...Figure 73 Configuring Interfaces for MSDP Multicast Source Discovery Protocol MSDP 477 ...
Page 478: ...Figure 74 Configuring OSPF and BGP for MSDP 478 Multicast Source Discovery Protocol MSDP ...
Page 483: ...Figure 77 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 483 ...
Page 484: ...Figure 78 MSDP Default Peer Scenario 3 484 Multicast Source Discovery Protocol MSDP ...
Page 745: ...Figure 104 Single and Double Tag TPID Match Service Provider Bridging 745 ...
Page 746: ...Figure 105 Single and Double Tag First byte TPID Match 746 Service Provider Bridging ...