HC120112003 BGP路由聚合

1、Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. BGP路由聚合Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page1前 言BGP作为一个跨域路由协议，在很多情况下都需要对明细路由进行聚合，并通告到其它远端的AS，而我们将会在本课程中讨论BGP聚合后的路径属性变化情况以及聚合后所引起的问题。Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Pag

2、e2培训目标学完本课程后，您应该能：l知道BGP路由聚合的方法l了解AS_PATH属性的变化l知道BGP路由聚合配置l知道BGP路由聚合策略Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page3目 录 什么是路由聚合 AS_SET改变路由聚合属性Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page4目 录 什么是路由聚合什么是路由聚合 AS_SET改变路由聚合属性Copyright 2012 Huawei Technol

3、ogies Co., Ltd. All rights reserved. Page5路由聚合概述BGP协议可以使用命令，将具体路由聚合成一条聚合路由。192.168.1.16/28192.168.1.32/28192.168.1.48/28192.168.1.0/26路由表192.168.1.16/28192.168.1.32/28192.168.1.48/28路由表192.168.1.0/26Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page6路由聚合原则十进制十进制二进制二进制192.168.1.16

4、11000000.10101000.00000001.00010000192.168.1.3211000000.10101000.00000001.00100000192.168.1.4811000000.10101000.00000001.0011000026 位位6 位位聚合后的路由：192.168.1.0/26Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page7BGP路由聚合种类自动聚合自动聚合l对BGP引入的IGP子网路由进行自然掩码聚合。配置自动聚合后，生成聚合后的自然网段路由，而原引入的子网路

5、由被抑制，不会被优选和发布给BGP邻居。AS-100AS-101192.168.1.1/32192.168.1.2/32192.168.1.3/32RTARTBRTAbgp 100RTA-bgpimport-route directRTA-bgppeer 10.1.1.2 as-num 101RTA-bgpsummary automaticRTBdisplay bgp routing-table Status codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Or

6、igin : i - IGP, e - EGP, ? - incomplete Network NextHop Path/Ogn * 10.0.0.0 10.1.1.1 100? * 192.168.1.0 10.1.1.1 100?10.1.1.110.1.1.2Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page8BGP路由聚合种类手动聚合手动聚合l对BGP本地路由进行聚合。通常情况下，手动聚合的优先级高于自动聚合的优先级192.168.1.1/32192.168.1.2/32192.168.1.3/3

7、2RTARTBAS-100AS-101RTAbgp 100RTA-bgpnetwork 192.168.1.1 255.255.255.255RTA-bgpnetwork 192.168.1.1 255.255.255.255RTA-bgpnetwork 192.168.1.1 255.255.255.255RTA-bgppeer 10.1.1.2 as-num 101RTA-bgpaggregate 192.168.1.0 24 detail-suppressed10.1.1.110.1.1.2RTBdisplay bgp routing-table Status codes: * - va

8、lid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Network NextHop Path/Ogn * 192.168.1.0 10.1.1.1 100iCopyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page9BGP路由聚合需要考虑的问题BGP路由聚合需要考虑的问题l明细路由的发布lBGP路由属性的继承nAS-PathnO

9、riginnCommunityn Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page10目 录 什么是路由聚合 AS_SET改变路由聚合属性Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page11不带AS_SET的路由聚合AS-100AS-400AS-300AS-200RTDRTCRTARTB160.20.0.0/16160.10.0.0/16aggregate 160.0.0.0 255.0.0.0 detail-s

10、uppressedCopyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page12AS-100AS-400AS-300AS-200RTDRTCRTARTB160.20.0.0/16160.10.0.0/16不带AS_SET的路由聚合RTC display bgp routing-tableStatus codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP,

11、 e - EGP, ? - incomplete Network NextHop Path/Ogn * 160.0.0.0/8 127.0.0.1 i s 160.10.0.0 10.2.2.2 200 i s 160.20.0.0 11.1.1.2 100 i10.2.2.211.1.1.2Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page13不带AS_SET的路由聚合AS-400AS-300RTCRTD聚合路由 160.0.0.0/8 被认为是始发于 AS-300，并且丢失了所有具体路由 160.10

12、.0.0/16 和 160.20.0.0/16 的AS-PATH信息。RTD display bgp routing-tableStatus codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Network NextHop Path/Ogn * 160.0.0.0/84.4.4.1 300 i4.4.4.14.4.4.2Copyright 2012 Huawei Technolog

13、ies Co., Ltd. All rights reserved. Page14带AS_SET的路由聚合AS-100AS-400AS-300AS-200RTDRTCRTARTB160.20.0.0/16160.10.0.0/16aggregate 160.0.0.0 255.0.0.0 detail-suppressed as-setCopyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page15带AS_SET的路由聚合AS-100AS-400AS-300AS-200RTDRTCRTARTB160.20.0.0/

14、16160.10.0.0/16RTC display bgp routing-tableStatus codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Network NextHop Path/Ogn * 160.0.0.0/8 127.0.0.1 200 100 i s 160.10.0.0 10.2.2.2 200 i s 160.20.0.0 11.1.1.2 100 i10

15、.2.2.211.1.1.2Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page16带AS_SET的路由聚合RTD display bgp routing-tableStatus codes: * - valid, - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Network NextHop Path/Ogn * 160.0.

16、0.0/84.4.4.1300 200 100 iAS-400AS-300RTCRTDAS_SET信息在避免路由环路时很重要，因为它记录了被聚合路由所经过的AS。Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page17带AS_SET的路由聚合AS-100AS-400AS-300AS-200RTDRTCRTARTB160.20.0.0/16160.10.0.0/16RTD display bgp routing-table Network NextHop Path/Ogn * 160.0.0.0/84.4.4

17、.1 300 200 iXCopyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page18目 录 什么是路由聚合 AS_SET改变路由聚合属性改变路由聚合属性Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page19聚合路由的问题聚合路由不继承原有BGP路由属性可以通过命令修改聚合路由属性：aggregate ip-address mask as-set | attribute-policy route-policy-name1

18、| detail-suppressed | origin-policy route-policy-name2 | suppress-policy route-policy-name3 Copyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page20Attribute-PolicyAS-100AS-400AS-300AS-200RTDRTCRTARTB160.20.0.0/16160.10.0.0/16Aggregate 160.0.0.0 255.0.0.0 detail-suppressed attribute-policy att1#route-policy att1 permit node 10 apply origin incompleteCopyright 2012 Huawei Technologies Co., Ltd. All rights reserved. Page21Attribute-PolicyAS-100AS-400AS-300