What is IGP metric?
RFC 7311 defines an optional non-transitive BGP attribute called the Accumulated IGP Metric Attribute (AIGP). As we know, IGP stands for Interior Gateway Protocol and represents a group of routing protocols that run within a single administrative domain. Each link is assigned a particular metric value.
Is BGP used for IGP?
IGP means Interior Routing Protocol, and EGP – Exterior Routing Protocol. OSPF, IS-IS, RIP and EIGRP are IGP Protocols. BGP is the only available EGP Protocol. The original intent of protocol designers was to use IGP within the boundaries of a network and EGP outside of these boundaries.
What is Aigp attribute?
AIGP stands for Accumulated IGP Metric Attribute which is specified in RFC 7311. IGPs (Interior Gateway Protocols) are designed to run within a single administrative domain and they make path-selection decision based on metric value.
Can BGP work without IGP?
No IGP was used. Before a BGP route is advertised and added to the routing table, this route must be known via an IGP. For the case of AS65000, no IGP is used, only pure iBGP peering hence BGP synchronization will stop bgp speaker from adding routes learned by its iBGP peer to its routing table.
What is BGP metric?
The BGP MED attribute, commonly referred to as the BGP metric, provides a means to convey to a neighboring Autonomous System (AS) a preferred entry point into the local AS. BGP MED is a non-transitive optional attribute and thus the receiving AS cannot propagate it across its AS borders.
What is BGP Aigp?
The accumulated IGP (AIGP) metric attribute for BGP enables deployment in which a single administration can run several contiguous BGP ASs. Such deployments allow BGP to make routing decisions based on the IGP metric. In such networks, it is possible for BGP to select paths based on metrics as is done by IGPs.
What is the difference between IGP and EGP?
Interior Gateway Protocol (IGP) is a Routing Protocol which is used to find network path information within an Autonomous System. Exterior Gateway Protocol (EGP) is a Routing Protocol which is used to find network path information between different Autonomous Systems.
What is the difference between internal and external BGP?
BGP supports these session types between neighbors: Internal (iBGP) – Runs between routers in the same autonomous system. External (eBGP) – Runs between routers in different autonomous systems.
What are the BGP attributes?
There are four categories of BGP attributes:
- Well-known mandatory: Recognized by all BGP peers, passed to all peers, and present in all Update messages.
- Well-known discretionary: Recognized by all routers, passed to all peers, and optionally included in the Update message.
- Optional transitive:
- Optional non-transitive:
Does MPLS require IGP?
RE: Why we need routing protocol in MPLS Speaking about “RSVP MPLS” in particular, one needs link-state IGP (not RIP, and not static routes) for loop prevention. Before sending out RSVP Path message, ingress LSR needs to build a loop-free ERO (Explicit Route Object).
What is locally originated in BGP?
1 Answer. Locally injected routes will always have a next hop of 0.0. 0.0 which means this is local to the router itself (connected), or learned from an IGP and injected into BGP with the ‘network’ command. These local routes will always have a weight of 32768 (highest) and will always be preferred.
Why BGP is preferred over OSPF?
BGP is considered to be more flexible as well as scalable than OSPF and it would be also used on a larger network. OSPF would be used to determine the fastest route whereas the BGP would be putting emphasis on determining the best path. Well, Because OSPF stub areas which would be a total mess to configure.