bgp basics

1. Border Gateway Protocol advertises, learns, and choosed the best paths inside the global internet.when both ISPs Conne CT, they typically use BGP to exchanges routing information. Enterprises sometimes use BGP to exchange routing information and one or more ISPs, allowing the enterprise routers to Le ARN Internet routes.2. BGP uses the robust Best-path algorit

Today, the BGP neighbor negotiation process found such a problem during the sorting process. BGP has 5 types of messages 1. open (code 1): used to establish a connection, including the version number (such as BGP3/BGP4) Hold Time = 180 s (it is a negotiation process, subject to a small Hold Time ), router-ID (OSPF and BGP can be manually configured), AS number (r

This blog article describes how to modify the next hop attribute value of NEXT_HOP through BGP, including modifying the next-hop attribute through next-hop-self, use route-map to modify the NEXT_HOP attribute values of BGP routes. 1. You can change the next-hop attribute through next-hop-self. When R5 is updated to the EBGP neighbor R2 BGP Route 5.5.5.0, N

, R1 in AS1, R2,R3,R4 in a large AS100 (R2,r3 in AS23, R4 in AS4), 5 in AS5.Standard Community Community Properties----A neighbor must open the transport Community propertiesR2#show Run | S Route-mapRoute-map AA Permit 10Match IP Address 1Set community Internet All-network can be passedRoute-map AA Permit 20Match IP Address 2Set community Local-as cannot outgoing small asRoute-map AA Permit 30Match IP Address 3Set community no-advertise cannot be passed to any neighborRoute-map AA Permit 40Match

BGP routing load balancing fault caseNetwork Architecture 1. Topology: the actual network structure is simplified considering the privacy of the company's network and a clearer description of fault phenomena. 2. network planning and data Configuration Overview: ◆ ASR9K establishes IBGP neighbor relationships with two n7ks Based on the interconnected addresses respectively; ◆ ASR9K is connected to the Cisco 752 architecture and 752 is used as the CDN s

MPLS + BGP advanced featuresWill LDP allocate tags for BGP routes? Why? --- Previously we mentioned that LDP assigns tags to IGP and never assigns tags to BGP. the following uses an experiment to illustrate how LDP + BGP works. forwarding method of a pure IP Network: In this topology, R1 and R4 establish an EBGP neighb

The BGP protocol is designed for routing between autonomous systems, but it can also be used inside autonomous systems and is a type of Dual Routing Protocol. Two BGP adjacent nodes that can communicate between autonomous systems must exist on the same physical link. BGP routers in the same autonomous system can communicate with each other to ensure that they sha

BGP Communities PropertiesThe community property of BGP is an optional transitive property, and routers that do not support this attribute pass the community value to the downstream BGP neighbor intact (provided that the delivery is configured Community property). the community attribute of BGP simplifies the matching

[Experimental environment] liehuo.net C3640-IK9O3S-M Version 12.4 (10) liehuo.net [Tutorial Objective] veryhuo.com Uses Full-mesh to resolve BGP routing black hole liehuo.net [Experiment topology] liehuo.net Liehuo.net [Experiment description] lie # fire # Network BGP distribution. R2, R3, and R4 run the OSPF protocol. The objective is to enable 1.1.1.1 BGP neig

Modify Weightrouter BGP 1 nrighbor [Address] weight 10 Modify single access-list 6 Permit 6.6.6.6N Bsp router-map XXX Permit 10 match IP address 6 N Bsp Set weight 20 router-map xxx permit 20router bap 1 neihgbor [address] Router-map xxx In2.local_preference:as Valid within, as within the pass, the default value is 100, compared to other as modified Local_preferenceroute-map XXX Permit 10 set local-preference 110router

1. Is the BGP Route table mentioned in the BGP protocol a BGP table? Which table does BGP actually use to route data packets? Is it a BGP table or an IP Route table? Are there any relationships between the two tables? For example, are some entries in the

Optional delivery-BGP Communities is a marker for routing entries to ensure continuity of routing filtering and selection-BGP routers can community the routing entries when redistribution, sending, and receiving routing updates (ROUTE-MAP)-Depending on the community value, the BGP router can filter incoming or outgoing routing updates or optimize certain routes-B

Technorati Tags: mpls,bgp,ccie, tags, LDPWill LDP assign tags to BGP routes? Why?650) this.width=650; "Style=" background-image:none;border-bottom:0px;border-left:0px;padding-left:0px; padding-right:0px;border-top:0px;border-right:0px;padding-top:0px; "title=" clip_image002 "border=" 0 "alt=" clip_ image002 "src=" http://s3.51cto.com/wyfs02/M02/73/F4/wKiom1YKXeDji6JDAADrM1sEj0Q970.jpg "height=" 178 "/>Befor

First, the experimental topology:Second, the experimental requirements:1, R4, R1, R3, R2 respectively in the BGP process deployment neighbor Send Community attribute command;2, R4 deployment ACL crawl 4.4.4.4 traffic, Route-map named as, call ACL, set community Local-as, and call Route-map as out in the BGP process;3, verify: R1, R3 have 4.4.4.4, but R2 have no 4.4.4.0 route entry?Third, command deployment:

1. Characteristics Use the Tcp179 port to build a neighbor, not to use multicast or broadcast, so you can only set up a neighbor by hand unicast 2. Four kinds of packages Open package: For building a neighbor relationship, use only when building a neighbor, when the neighbor is established, no longer send KeepAlive package: Used to keep a neighbor relationship, it plus open is equivalent to the IGP Hello package. Send once every 60 seconds, holdtime 180 seconds Update package: Contains the

Key Issues 1) How does an ACL match route entries with the same subnet and different masks? How do I match entries with the same mask and different subnets? 2) Why does a summary route cause a tumble of BGP peers? 3) Why does the acl fail to match the route entry when attribite-map is used? 4) How to Use advertise-map, suppress-map, unsuppress-map, attribute-map, and route-map routing diagrams? Instance. 5) What are the two routing filtering solutions

1. Routes identified with R: IGP and BGP Learn the same route, but the IGP learns that the ad is smaller, and the route identifies the route that the R,r identity does not put in the routing table, but is still passed to the other neighbors. You can view the routes identified by the R by command show ip BGP rib-failure.2. Two methods of restarting BGP:Hard restart: Clear IP

Dynamic routing protocols are divided into Internal Gateway Protocol (IGP) and External Gateway Protocol (EGP), depending on whether they are used within an autonomous domain. The autonomous domain here refers to a network with a unified management authority and a unified routing policy. The routing protocol adopted within the autonomous domain is called the Internal Gateway Protocol, which is commonly used in RIPandOSPF, and theexternal Gateway protocol is mainly applied to routing between mult

CONFIG prefix-listRouter (config) #ip prefix-list list-name seq permit/deny network/len ge/lePrefix-list was originally designed for BGP. The network address part and mask portion of the routing entry can be matchedIP prefix-list NAME Permit 172.16.0.0/22 ge le 24/22: prefix 22bit the sameGe24: Mask range min. 24 bitsLe24: Mask range Max 24 bitsWhen there is no GE, the mask range is the smallest and the prefix is the sameWhen there is GE, there is no

Basic Configuration: R1: Router bgp 9806 Nei too many connections 20 remote-as 4808 Bgp router-id 1.1.1.1 R2: Router bgp 4808 Nei 1.1.1.1 remote-as 9806 Nei 1.1.1.1 update-source lo0 Bgp router-id 255.255.255.255.20 Network bandwidth limit 21 mask limit 255 Only the bgp neig