Cisco NX-OS/IOS BGP (Advanced) Comparison

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(New page: <font size = "3">'''Objective'''</font> This tech note outlines the main differences in advanced Border Gateway Protocol (BGP) support between Cisco® NX-OS Software and Cisco IOS® Soft...)
 
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<font size = "3">'''BGP Overview'''</font>
<font size = "3">'''BGP Overview'''</font>
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BGPv4 is a standard exterior routing protocol defined in RFC 4271, commonly used to exchange network reachability information between autonomous systems. This document discusses route reflectors, confederations, peer templates, route-map policies and the prefix-lists feature.
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BGPv4 is a standard exterior routing protocol defined in RFC 4271, commonly used to exchange network reachability information between autonomous systems. This document discusses route reflectors, confederations, peer templates, route-map policies and the prefix-list (route-filtering) feature.
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<font size = "3">'''Important Cisco NX-OS and Cisco IOS Softfware Differences'''</font>
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<font size = "3">'''Important Cisco NX-OS and Cisco IOS Software Differences'''</font>
In Cisco NX-OS:
In Cisco NX-OS:
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{| border="1" cellpadding="2"
{| border="1" cellpadding="2"
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!width="225" align="left" style="background:#99CCFF;" |'''Cisco NX-OS BGP'''
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!width="270" align="left" style="background:#99CCFF;" |'''Cisco NX-OS BGP'''
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!width="225" align="left" style="background:#99CCFF;" |'''Cisco IOS Software BGP'''
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!width="270" align="left" style="background:#99CCFF;" |'''Cisco IOS Software BGP'''
!width="450" align="left" style="background:#99CCFF;" |'''Command Description'''
!width="450" align="left" style="background:#99CCFF;" |'''Command Description'''
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|-
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|'''show bgp convergence || - || Displays global convergence information
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|-
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|'''show bgp process || - || Displays global BGP process information
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|-
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|'''show bgp sessions || - || Displays information for all neighbors
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|-
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|'''show bgp statistics || - || Displays global BGP process statistics
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|-
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| <font color="white"> - || <font color="white"> - || <font color="white"> -
|-
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|'''show ip bgp''' ''<option>''|| show ip bgp || Displays BGP Process and BGP table entries
|'''show ip bgp''' ''<option>''|| show ip bgp || Displays BGP Process and BGP table entries
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|-
|-
|'''show ip bgp community no-export-spoofed'''|| - || Displays BGP routes not sent to outside local AS
|'''show ip bgp community no-export-spoofed'''|| - || Displays BGP routes not sent to outside local AS
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|-
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|<b>show ip bgp community-list</b> <i><name></i>|| show ip bgp community-list <i><name></i> || Displays a specific BGP community list
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|'''show ip bgp dampening dampened-paths'''|| show ip bgp dampening dampened-paths || Displays all Dampened paths
|'''show ip bgp dampening dampened-paths'''|| show ip bgp dampening dampened-paths || Displays all Dampened paths
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|-
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|'''show ip bgp dampening parameters'''|| show ip bgp dampening parameters || Displays all of the Dampening parameters
|'''show ip bgp dampening parameters'''|| show ip bgp dampening parameters || Displays all of the Dampening parameters
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|-
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|'''show ip bgp extcommunity''' ''<word>''|| - || Displays routes with a specific regular expression for extended communities
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|-
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|'''show ip bgp extcommunity-list''' ''<name>''|| - || Displays a specific BGP extended community list
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|'''show ip bgp filter-list'''|| show ip bgp filter-list || Displays all routes matching a specified filter list
|'''show ip bgp filter-list'''|| show ip bgp filter-list || Displays all routes matching a specified filter list
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|'''show ip bgp neighbors''' ''x.x.x.x''|| show ip bgp neighbors ''x.x.x.x'' || Displays detailed information for a neighbor
|'''show ip bgp neighbors''' ''x.x.x.x''|| show ip bgp neighbors ''x.x.x.x'' || Displays detailed information for a neighbor
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|-
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|'''show ip bgp nexhop ''' ''x.x.x.x''|| - || Displays all routes matching a specified next-hop
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|'''show ip bgp nexthop ''' ''x.x.x.x''|| - || Displays all routes matching a specified next-hop
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|-
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|'''show ip bgp nexthop-database''' || - || Displays the next-hop database
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|'''show ip bgp paths'''|| show ip bgp paths || Displays all BGP paths
|'''show ip bgp paths'''|| show ip bgp paths || Displays all BGP paths
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|'''show ip bgp regexp'''|| show ip bgp regexp || Displays routes matching a regular-expression
|'''show ip bgp regexp'''|| show ip bgp regexp || Displays routes matching a regular-expression
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|-
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|'''show ip bgp received-paths'''|| - || Displays the paths stored for soft reconfiguration
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|'''show ip bgp route-map'''|| show ip bgp route-map || Displays BGP routes matching a route-map
|'''show ip bgp route-map'''|| show ip bgp route-map || Displays BGP routes matching a route-map

Latest revision as of 22:28, 17 November 2012

Objective

This tech note outlines the main differences in advanced Border Gateway Protocol (BGP) support between Cisco® NX-OS Software and Cisco IOS® Software. Sample configurations are included for Cisco NX-OS and Cisco IOS Software for some common features to demonstrate the similarities and differences. Please refer to the NX-OS documentation on Cisco.com for a complete list of supported features.


BGP Overview

BGPv4 is a standard exterior routing protocol defined in RFC 4271, commonly used to exchange network reachability information between autonomous systems. This document discusses route reflectors, confederations, peer templates, route-map policies and the prefix-list (route-filtering) feature.


Important Cisco NX-OS and Cisco IOS Software Differences

In Cisco NX-OS:

  • When configuring route reflectors, the route-reflector-client command is assigned per neighbor under the neighbor-specific address family.
  • When configuring confederations, the confederation is configured under the autonomous system without the leading bgp keyword.
  • Cisco NX-OS uses a peer template instead of a peer group to reuse common BGP policies.
  • Multiple policy templates can be applied to a single neighbor. Cisco IOS Software allows only one policy template per neighbor.
  • Cisco NX-OS does not require a manual reset for a neighbor when its routing policy is modified. Cisco IOS Software requires a hard or soft reset depending on the neighbor capabilities exchanged.


Things You Should Know

The following list provides some additional facts about Cisco NX-OS that should be helpful when designing, configuring, and maintaining an advanced BGP network configuration.


  • Peer and session templates define neighbor attributes such as security passwords, timers, and transport options.
  • Peer templates and session templates have identical configuration capabilities with one exception: peer templates can configure address families.
  • Peer and session templates are inherited by a neighbor through the BGP neighbor configuration mode.
  • Only one peer template and session template can be inherited by a single BGP neighbor.
  • Peer templates can inherit session templates.
  • Session templates can inherit other session templates.
  • Policy templates define address-family policies for inbound or outbound polices, including default-route origination, filter lists, route-map polices, prefix lists, etc.
  • Multiple policy templates can be assigned per neighbor. Policy templates are executed in order based on the configured sequence number.
  • Policy templates are inherited by a neighbor through the neighbor and address-family configuration mode.
  • Route-map polices can configure BGP attributes such as as-path, community lists, community attributes, dampening, local preference, metric type, origin, and weight.
  • Route-map polices can be applied per neighbor for inbound and outbound routing policies.


Configuration Comparison


The following sample code shows the configuration similarities and differences between the Cisco NX-OS and Cisco IOS Software CLIs. The configurations are very similar with the exception of the hierarchy used in Cisco NX-OS.


Cisco IOS CLI Cisco NX-OS CLI
Configuring a Route-Reflector
router bgp 10

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.2.1 remote-as 10

neighbor 192.168.2.1 update-source Loopback0

neighbor 192.168.2.1 route-reflector-client

no auto-summary

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

neighbor 192.168.2.1 remote-as 10

update-source loopback0

address-family ipv4 unicast

route-reflector-client

Configuring Confederations
router bgp

no synchronization

bgp confederation identifier 10

bgp confederation peers 65535

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.10.2 remote-as 65535

no auto-summary

router bgp 65534

confederation identifier 10

confederation peers 65535

address-family ipv4 unicast

network 192.168.11.1/32

neighbor 192.168.10.2 remote-as 65535

address-family ipv4 unicast

Configuring a Peer Template
router bgp 10

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor IBGP-Template peer-group

neighbor IBGP-Template password cisco123

neighbor IBGP-Template update-source Loopback0

neighbor 192.168.2.1 remote-as 10

neighbor 192.168.2.1 peer-group IBGP-Template

no auto-summary

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

template peer IBGP-Template

password 3 a667d47acc18ea6b

update-source loopback0

address-family ipv4 unicast

neighbor 192.168.2.1 remote-as 10

inherit peer IBGP-Template

Configuring a Policy Template
router bgp 10

template peer-policy EBGP-Policy

default-originate

send-community

exit-peer-policy


no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.10.2 remote-as 20

neighbor 192.168.10.2 inherit peer-policy EBGP-Policy

no auto-summary

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

template peer-policy EBGP-Policy

send-community

default-originate

neighbor 192.168.10.2 remote-as 20

address-family ipv4 unicast

inherit peer-policy EBGP-Policy 10

Configuring an Outbound Neighbor Route-Map Policy
route-map EBGP-Policy permit 10

set as-path prepend 10 10 10


router bgp 10

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.10.2 remote-as 20

neighbor 192.168.10.2 route-map EBGP-Policy out

no auto-summary

route-map EBGP-Policy permit 10

set as-path prepend 10 10 10


router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

neighbor 192.168.10.2 remote-as 20

address-family ipv4 unicast

route-map EBGP-Policy out

Configuring an Outbound Prefix-List
ip prefix-list EBGP-Policy seq 5 permit 192.168.11.1/32


router bgp 10

no synchronization

neighbor 192.168.10.2 remote-as 20

neighbor 192.168.10.2 prefix-list EBGP-Policy out

no auto-summary

ip prefix-list EBGP-Policy seq 5 permit 192.168.11.1/32


router bgp 10

neighbor 192.168.10.2 remote-as 20

address-family ipv4 unicast

prefix-list EBGP-Policy out



Verification Command Comparison

The following table compares some useful show commands for verifying and troubleshooting a BGP network configuration.


Cisco NX-OS BGP Cisco IOS Software BGP Command Description
show bgp convergence - Displays global convergence information
show bgp process - Displays global BGP process information
show bgp sessions - Displays information for all neighbors
show bgp statistics - Displays global BGP process statistics
- - -
show ip bgp <option> show ip bgp Displays BGP Process and BGP table entries
show ip bgp x.x.x.x show ip bgp x.x.x.x Displays a specific network in the BGP table
show ip bgp x.x.x.x vrf - Displays a network in a specified VRF BGP table
show ip bgp x.x.x.x/len show ip bgp x.x.x.x mask Displays a specific prefix in the BGP table
show ip bgp x.x.x.x/len longer-prefix show ip bgp x.x.x.x mask longer-prefix Displays a prefix in the table with longer prefixes
show ip bgp all show ip bgp all Displays the BGP table for all protocol families
show ip bgp community <word> show ip bgp community <#> Displays routes with a specific regular expression
show ip bgp community <aa:nn> - Displays routes with a specific community value
show ip bgp community internet - Displays BGP routes advertised to the Internet
show ip bgp community no-advertise show ip bgp community no-advertise Displays BGP routes not advertised to peers
show ip bgp community no-export show ip bgp community no-export Displays BGP routes not exported to next AS
show ip bgp community no-export-spoofed - Displays BGP routes not sent to outside local AS
show ip bgp community-list <name> show ip bgp community-list <name> Displays a specific BGP community list
show ip bgp dampening dampened-paths show ip bgp dampening dampened-paths Displays all Dampened paths
show ip bgp dampening flap-statistics show ip bgp dampening flap-statistics Displays flap statistics for BGP routes
show ip bgp dampening history-paths - Displays all history paths
show ip bgp dampening parameters show ip bgp dampening parameters Displays all of the Dampening parameters
show ip bgp extcommunity <word> - Displays routes with a specific regular expression for extended communities
show ip bgp extcommunity-list <name> - Displays a specific BGP extended community list
show ip bgp filter-list show ip bgp filter-list Displays all routes matching a specified filter list
show ip bgp flap-statistics - Displays all BGP route flap statistics
show ip bgp ipv4 multicast <option> show ip bgp ipv4 multicast <option> Displays BGP IPv4 multicast address families
show ip bgp ipv4 unicast <option> show ip bgp ipv4 unicast <option> Displays BGP IPv4 unicast address families
show ip bgp neighbors show ip bgp neighbors Displays detailed neighbor information
show ip bgp neighbors x.x.x.x show ip bgp neighbors x.x.x.x Displays detailed information for a neighbor
show ip bgp nexthop x.x.x.x - Displays all routes matching a specified next-hop
show ip bgp nexthop-database - Displays the next-hop database
show ip bgp paths show ip bgp paths Displays all BGP paths
show ip bgp peer-policy - Displays BGP peer policy by specified name
show ip bgp peer-session - Displays information about a peer session
show ip bgp peer-template show ip bgp unicast ipv4 template Displays information about a peer template
show ip bgp prefix-list show ip bgp prefix-list Displays routes matching a specified prefix-list
show ip bgp regexp show ip bgp regexp Displays routes matching a regular-expression
show ip bgp received-paths - Displays the paths stored for soft reconfiguration
show ip bgp route-map show ip bgp route-map Displays BGP routes matching a route-map
show ip bgp summary show ip bgp summary Displays a summary list of neighbors and statistics
show ip bgp vrf show ip bgp vpnv4 vrf Displays information for a specified BGP VRF

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