Key points of BGP

[M.Sultan]

What is the most significant knowledge about BGP that we must always remember ?

[MHM Cisco World]

The 7 (or 9) criteria of select the best path.

You must always remember these criteria 

[Blue_Bird · Accepted solution]

1) BGP fundamentals:

BGP peering relationship(iBGP vs eBGP), bgp messages, bgp states, next-hop-self and update-source

commands

2) BGP Filtering:

Filtering networks with prefix-list,Distribute-list, AS-Path ACL, Route-maps

3) BGP path selection: working bgp path selection attributes....( weight, local preference, as-path, origin, med....)

Best regards
******* If This Helps, Please Rate *******

[David Ruess]

This document:

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html

-David

[Joseph W. Doherty]

It's suitable usage purpose.

[Richard Burts]

There are many important things to understand. Here are a few of them:

- our IGPs frequently use the network statement to identify which interfaces the routing protocol will run on. BGP uses the network statement not to identify interfaces but to identify what networks it should advertise.

- our IGPs use the interfaces where it is running to dynamically discover

neighbors

and to negotiate

neighbor relationships

BGP does not dynamically discover

neighbors

but uses the

neighbor

command to identify

neighbors

- when BGP establishes a

neighbor relationship

it characterizes the relationship as External (EBGP) or Internal (IBGP) and uses different policies in communication with the

neighbor

IGPs do not do this.

[Joseph W. Doherty]

---

@Richard Burts wrote:

- when BGP establishes a

neighbor relationship

it characterizes the relationship as External (EBGP) or Internal (IBGP) and uses different policies in communication with the

neighbor

. IGPs do not do this.

---

Well . . .

Perhaps OSPF's areas (zero vs. non-zero) and/or IS-IS areas (L2 vs. L1), both are somewhat analogous to BGP's eBGP/iBGP "policy" communications change between

neighbors

.(?)

---

@Richard Burts wrote:

- our IGPs frequently use the network statement to identify which interfaces the routing protocol will run on. BGP uses the network statement not to identify interfaces but to identify what networks it should advertise.

Then there's IS-IS which doesn't use a network statement.