A következő feladattal találkoztam: BGP Multi-home-t kellene létrehozni két ISP felé. Ez valójában azt jelenti, hogy a saját AS-ünk két másik AS-hez fog csatlakozni a BGP segítségével. A teszt hálózatot állítottam, és különös dologra figyeltem fel. A BGP1 routing táblájában egy adott prefixhez nem két next-hop tartozott, hanem csak egy.

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Popularity: 45% [?]

QoS Policy Propagation via BGP (QPPB), ez a feature lehetőséget ad arra hogy BGP attribútumokat és prefixeket képezzünk le CEF paraméterekre. Ezzel forgalom szabályokat tudunk érvényesíteni, és átvinni a hálózaton. Joe Harris oldalán található róla egy leírás. Leírás a cisco oldalán: Configuring QPPB

The Border Gateway Protocol (BGP) is an interdomain routing protocol that exchanges reachability information with other BGP systems. It is defined by RFC 1163. The Policy Propagation via BGP feature allows you to classify packets based on the following: • Access lists. • BGP community lists. A community is a group of destinations that share some common attribute. You use community lists to create groups of communities to use in a match clause of a route map. As with access lists, a series of community lists can be created. • BGP autonomous system paths. An autonomous system path is a collection of networks under a common administration sharing a common routing strategy. BGP carries the autonomous system path in its routing updates. You can filter routing updates by specifying an access list on both incoming and outbound updates based on the BGP autonomous system path. • IP Precedence. See the section " About IP Precedence" earlier in this chapter. • Source and destination address lookup. You can specify whether the IP Precedence level is obtained from the source (input) address or destination (output) address entry in the route table. After a packet has been classified using BGP, you can use other QoS features such as CAR and WRED to specify and enforce business policies to fit your business model. BGP Policy Propagation leverages BGP to distribute QoS policy to remote routers in your network. It allows ingress routers to prioritize incoming traffic.

Popularity: 48% [?]

Csináltam egy gyors tesztet a BGP működésével kapcsolatban. Két router össze van kötve serial link-n. A BGP Load-balancing működik?

(a konfig itt , de kiváncsi voltam Dynamips-el működik-e)

R0:

R0(config)#int s1/0
R0(config-if)# ip address 10.0.1.9 255.255.255.252
R0(config-if)# encapsulation ppp
R0(config-if)#exi
R0(config)#int s1/1
R0(config-if)# ip address 10.0.1.9 255.255.255.252
R0(config-if)# encapsulation ppp
R0(config-if)#exi
R0(config)#router bgp 11
R0(config-router)# bgp log-neighbor-changes
R0(config-router)# neighbor 10.0.1.10 remote-as 12
R0(config-router)#exi
R0(config)#exi

R1:

R1(config)#int s1/0
R1(config-if)# ip address 10.0.1.10 255.255.255.252
R1(config-if)# encapsulation ppp
R1(config-if)#exi
R1(config)#int s1/1
R1(config-if)# ip address 10.0.1.10 255.255.255.252
R1(config-if)# encapsulation ppp
R1(config-if)#exi
R1(config)#router bgp 12
R1(config-router)# bgp log-neighbor-changes
R1(config-router)# network 172.16.0.0
R1(config-router)# neighbor 10.0.1.9 remote-as 11
R1(config-router)#exi
R1(config)#ip route 172.16.0.0 255.255.0.0 Null0

R0-n: A BGP OPEN Message..

R0#debug ip bgp all
BGP debugging is on for all address families
R0#
*Dec 13 20:08:57.791: BGP: 10.0.1.10 open active, local address 10.0.1.9
*Dec 13 20:08:57.835: BGP: 10.0.1.10 went from Active to OpenSent
*Dec 13 20:08:57.839: BGP: 10.0.1.10 sending OPEN, version 4, my as: 11, holdtim
e 180 seconds
*Dec 13 20:08:57.843: BGP: 10.0.1.10 send message type 1, length (incl. header)
45
*Dec 13 20:08:57.883: BGP: 10.0.1.10 rcv message type 1, length (excl. header) 2
6
*Dec 13 20:08:57.883: BGP: 10.0.1.10 rcv OPEN, version 4, holdtime 180 seconds
*Dec 13 20:08:57.887: BGP: 10.0.1.10 rcv OPEN w/ OPTION parameter len: 16
*Dec 13 20:08:57.887: BGP: 10.0.1.10 rcvd OPEN w/ optional parameter type 2 (Cap
ability) len 6
*Dec 13 20:08:57.887: BGP: 10.0.1.10 OPEN has CAPABILITY code: 1, length 4
*Dec 13 20:08:57.887: BGP: 10.0.1.10 OPEN has MP_EXT CAP for afi/safi: 1/1
*Dec 13 20:08:57.887: BGP: 10.0.1.10 rcvd OPEN w/ optional parameter type 2 (Cap
ability) len 2
*Dec 13 20:08:57.891: BGP: 10.0.1.10 OPEN has CAPABILITY code: 128, length 0
*Dec 13 20:08:57.891: BGP: 10.0.1.10 OPEN has ROUTE-REFRESH capability(old) for
all address-families
*Dec 13 20:08:57.891: BGP: 10.0.1.10 rcvd OPEN w/ optional parameter type 2 (Cap
ability) len 2
*Dec 13 20:08:57.891: BGP: 10.0.1.10 OPEN has CAPABILITY code: 2, length 0
*Dec 13 20:08:57.891: BGP: 10.0.1.10 OPEN has ROUTE-REFRESH capability(new) for
all address-families
BGP: 10.0.1.10 rcvd OPEN w/ remote AS 12
*Dec 13 20:08:57.891: BGP: 10.0.1.10 went from OpenSent to OpenConfirm
*Dec 13 20:08:57.891: BGP: 10.0.1.10 went from OpenConfirm to Established
*Dec 13 20:08:57.891: %BGP-5-ADJCHANGE: neighbor 10.0.1.10 Up

R0-n látszik a 172.16.0.0 hálózat:

R0#sh ip route bgp
B 172.16.0.0/16 [20/0] via 10.0.1.10, 00:08:08
R0#

És load-balancing???? Igen:)

R0#sh ip cef 172.16.0.0 internal
172.16.0.0/16, version 12, epoch 0, per-destination sharing
0 packets, 0 bytes
via 10.0.1.10, 0 dependencies, recursive
next hop 10.0.1.10, Serial1/1 via 10.0.1.10/32
valid adjacency

Recursive load sharing using 10.0.1.10/32
Load distribution: 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 (refcount 2)

Hash OK Interface Address Packets
1 Y Serial1/0 point2point 0
2 Y Serial1/1 point2point 0
3 Y Serial1/0 point2point 0
4 Y Serial1/1 point2point 0
5 Y Serial1/0 point2point 0
6 Y Serial1/1 point2point 0
7 Y Serial1/0 point2point 0
8 Y Serial1/1 point2point 0
9 Y Serial1/0 point2point 0
10 Y Serial1/1 point2point 0
11 Y Serial1/0 point2point 0
12 Y Serial1/1 point2point 0
13 Y Serial1/0 point2point 0
14 Y Serial1/1 point2point 0
15 Y Serial1/0 point2point 0
16 Y Serial1/1 point2point 0
refcount 5

Na megyek tanulni zh-ra…

Popularity: 26% [?]