BGP Overview Sumanta Das Gajendra Mahapatra. Content 1.Introduction 2.Session Establishment 3.Route processing 4.Basic Configuration 5.BGP Police.

BGP Overview

Sumanta Das Gajendra Mahapatra

Content

1. Introduction

2. Session Establishment

3. Route processing

4. Basic Configuration

5. BGP Police

Introduction to BGP

- BGP : Broader Gateway Protocol

- Why Need BGP

Introduction to BGP

Introduction to BGP

Introduction to BGP

Introduction to BGP

BGP Characteristics :1. BGP is distance vector protocol with

enhancement - reliable update - Triggered updates only - Rich metrics (called path attributes)Designed to scale to huge internetworks

Introduction to BGP

IBGPEBGP

BGP Session Establishment

-Neighbor discovery - Hold Times-Keepalive

BGP Session Establishment

BGP Session Establishment

BGP Session Establishment

BGP Route Processing

BGP Route Processing

BGP Route Processing

Routing Loop:

IBGP: Split Horizon

EBGP: AS path info

Basic BGP Configuration

-Configuration command -Monitoring Command-Debug Command

Basic BGP Configuration

BGP Routing process :Router(config)#router bgp as-number

Configuring External Neighbors :Router(config-router)#neighbor ip-address remote-as as-number

To temporarily disable a BGP neighbor:Router(config-router)#neighbor ip-address shutdown

Configuring BGP Timers:Router(config-router)#timers bgp keepalive holdtime

Per Specific neighbor:Router(config-router)#neighbor [ ip address | peer group name ] timers keepalive holdtime

Basic BGP Configuration

Configuring MD5 Authentication:Router(config-router)#neighbor ip-address password string

Router(config-router)#no auto-summary

Aggregating BGP networksRouter(config-router)#aggregate-address address-prefix mask Router(config-router)#aggregate-address address-prefix mask

summary-only

Basic BGP Configuration

Basic BGP Configuration

BGP command for monitoring:

Monitorior neighber info:Router>show ip bgp summary

Monitor BGP neighbors on details:Router>show ip bgp neighbor ip-address

Monitor bgp table:Router > show ip bgp

Basic BGP Configuration

Debugging BGP :

Display all tcp transaction :

Router#debug ip tcp transactions

Display significant BGP event

Router#Debug ip bgp events

Debug BGp keepalive packets :

Router#debug ip bgp keepaklives

Display all incoming and outgoing BGp updates :

Router#debug ip bgp updates

BGP Policies

Needs of BGP policy

BGP Police

BGP Filters :

BGP Police

BGP Filters:

BGP Police

BGP Police

BGP Filters :

- As-Path Filters

- Prefix-List Filters

- Outbound Filters

- Route-Maps

BGP Police

BGP Filters :

- As-Path Filters

BGP Police

BGP Filters :

- As-Path Filters

Configuring BGP AS-Path Filters

Router(Config)#ip as-path access-list number permit | deny regexp

Router(Config-router)#neighbor ip-address filter-list as-path-filter in|out

BGP Police

BGP Filters :

- prefix-Based Filters

BGP Police

BGP Filters :

- prefix-Based Filters

Configuration:

router(config-router)#neighbor {ip address| peer-group-name } prefix-list list {in| out}

Router(config-routeer)#distribution-list prefix-list prefix-list out routing-process

BGP Police

BGP Filters :

- Outbound Router Filter

BGP Police

Outbound Router Filter ORF format

ORF message consist of the following fields

-AFI/SAFI

-ORF type

-When to refresh

-List of ORF entries

ORF entries depends on the ORF type

ORF capability needs to be negotiated for every supported ORF type

BGP Police

BGP Filters :

- Route-map BGP Filters :

BGP Police

BGP Filters :

- Route-map BGP Filters :

BGP Police

BGP Filters :

- Route-map BGP Filters :