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 :
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