BGP和OSPF在路由重分发时的注意点.docx
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BGP和OSPF在路由重分发时的注意点
RGNOSv10.3(3)
BGP和OSPF在路由重分发时的注意点
2008-5-15
福建星网锐捷网络有限公司
版权所有XX
前言
本文档介绍了RGNOSV10.3(3)中BGP和OSPF路由重发布时的一些实现特点。
由于这些特点区别于友商CISCO的BGP功能实现,在具体的项目实施过程中需要注意。
1.☹ 本文档仅限公司内部使用,严禁外传。
1.☺ 如果您在阅读中产生疑问,请与文档维护人联系。
1.1 OSPF重分发BGP路由
1.1.1 注意点
1.K 这里Cisco验证的版本为c7200-adventerprisek9-mz.124-9.T1.bin
项目
Ruijie
Cisco
备注
BGP路由的下发
BGP不会将直连路由下发到核心路由表,因此重分发BGP路由的时候是没有BGP的直连路由
BGP会将BGP的直连路由下发到核心路由表,因此重分发BGP路由的时候,会重分发BGP的直连路由
解决方法:
在OSPF配置BGP的直连路由,参看“重分发BGP的直连路由”。
重分发IBGP路由
默认重分发所有BGP路由
默认不允许重分发BGP的IBGP路由。
在BGP配置模式下可以使用bgpredistribute-internal命令允许IGP协议重分发IBGP路由
解决方法:
1、RGNOSv10.3(4)将增加支持bgpredistribute-internal功能;
2、使用route-map的matchroute-type功能,参看“重分发IBGP路由”。
BGP路由下发的控制
不对下发的路由进行控制
可以使用table-map修改下发到核心路由表的路由属性
解决方法:
1、RGNOSv10.3(4)将增加支持table-map功能。
2.1.2 应用实例
1.1.2.1 网络拓扑
四台设备之间建立EBGP/IBGP/EBGP连接。
C1为CISCO3550、C2、C3是Cisco模拟器,R1是我司设备,实验设备为RG-S5750。
C1和R1建立EBGP连接,R1和C2建立IBGP连接,C2和C3建立EBGP连接。
其中C1和C3主要是发送路由,具体的操作在R1和C2。
2.1.2.2 配置文件
C1简化配置
C1#shorunning-config
Buildingconfiguration...
Currentconfiguration:
2557bytes
!
version12.2
noservicepad
servicetimestampsdebuguptime
servicetimestampsloguptime
noservicepassword-encryption
!
hostnameC1
!
!
noaaanew-model
ipsubnet-zero
iprouting
!
!
!
!
!
!
nofileverifyauto
spanning-treemodepvst
spanning-treeextendsystem-id
!
vlaninternalallocationpolicyascending
!
!
interfaceLoopback0
ipaddress1.1.1.1255.255.255.255
!
interfaceFastEthernet0/1
noswitchport
ipaddress192.168.16.1255.255.255.248
!
interfaceFastEthernet0/2
switchportmodedynamicdesirable
!
interfaceFastEthernet0/3
switchportmodedynamicdesirable
!
...
!
routerbgp1
nosynchronization
bgplog-neighbor-changes
redistributestatic
neighbor192.168.16.2remote-as23
noauto-summary
!
ipclassless
iproute192.168.111.0255.255.255.0Loopback0
iproute192.168.112.0255.255.255.0Loopback0
iphttpserver
iphttpsecure-server
!
!
!
control-plane
!
!
linecon0
linevty04
privilegelevel15
passwordw
login
!
!
end
C1#
C2简化配置
C2#shorunn
Buildingconfiguration...
Currentconfiguration:
1450bytes
!
version12.4
servicetimestampsdebugdatetimemsec
servicetimestampslogdatetimemsec
noservicepassword-encryption
!
hostnameC2
!
boot-start-marker
warm-reboot
boot-end-marker
!
!
noaaanew-model
!
resourcepolicy
!
ipcef
!
!
!
!
interfaceLoopback0
ipaddress192.168.125.1255.255.255.0secondary
ipaddress192.168.126.1255.255.255.0secondary
ipaddress2.2.2.2255.255.255.255
!
interfaceFastEthernet0/0
ipaddress192.168.26.2255.255.255.248
duplexfull
!
interfaceEthernet1/0
noipaddress
shutdown
duplexhalf
!
interfaceEthernet1/1
noipaddress
shutdown
duplexhalf
!
interfaceEthernet1/2
noipaddress
shutdown
duplexhalf
!
interfaceEthernet1/3
ipaddress192.168.23.1255.255.255.248
duplexfull
!
routerospf1
log-adjacency-changes
network2.2.2.20.0.0.0area0
network192.168.26.00.0.0.7area0
!
routerbgp23
nosynchronization
bgplog-neighbor-changes
network192.168.125.0
network192.168.126.0
neighbor6.6.6.6remote-as23
neighbor6.6.6.6update-sourceLoopback0
neighbor6.6.6.6next-hop-self
neighbor192.168.23.2remote-as3
noauto-summary
!
noiphttpserver
noiphttpsecure-server
!
!
...
!
linecon0
stopbits1
lineaux0
linevty04
privilegelevel15
passwordw
login
!
!
end
C2#
C3简化配置
C3#shorunn
Buildingconfiguration...
Currentconfiguration:
1178bytes
!
version12.4
servicetimestampsdebugdatetimemsec
servicetimestampslogdatetimemsec
noservicepassword-encryption
!
hostnameC3
!
boot-start-marker
boot-end-marker
!
!
noaaanew-model
!
resourcepolicy
!
ipcef
!
!
!
!
!
!
interfaceLoopback0
ipaddress3.3.3.3255.255.255.255
!
interfaceFastEthernet0/0
noipaddress
shutdown
duplexfull
!
interfaceEthernet1/0
noipaddress
shutdown
duplexhalf
!
interfaceEthernet1/1
noipaddress
shutdown
duplexhalf
!
interfaceEthernet1/2
noipaddress
shutdown
duplexhalf
!
interfaceEthernet1/3
ipaddress192.168.23.2255.255.255.248
duplexfull
!
routerbgp3
nosynchronization
bgplog-neighbor-changes
redistributestatic
neighbor192.168.23.1remote-as23
noauto-summary
!
iproute192.168.131.0255.255.255.0Loopback0
iproute192.168.132.0255.255.255.0Loopback0
noiphttpserver
noiphttpsecure-server
!
!
!
loggingalarminformational
!
...
!
linecon0
stopbits1
lineaux0
linevty04
privilegelevel15
passwordw
login
!
!
end
C2#
R1简化配置
R1#showrunn
Buildingconfiguration...
Currentconfiguration:
2080bytes
!
versionRGNOS10.3.00(3),Release(38105)(FriApr2515:
29:
44CST2008-ngcf31)
hostnameR1
co-operateenable
!
!
!
!
route-mapospf_redistpermit10
matchroute-typeexternal
!
vlan1
!
!
!
!
!
interfaceGigabitEthernet0/1
noswitchport
noipproxy-arp
ipaddress192.168.26.1255.255.255.248
!
interfaceGigabitEthernet0/2
!
...
!
interfaceGigabitEthernet0/23
!
interfaceGigabitEthernet0/24
noswitchport
noipproxy-arp
ipaddress192.168.16.2255.255.255.248
!
interfaceLoopback0
ipaddress6.6.6.6255.255.255.255
ipaddress192.168.165.1255.255.255.0secondary
ipaddress192.168.166.1255.255.255.0secondary
!
!
!
!
!
!
!
!
routerbgp23
neighbor2.2.2.2remote-as23
neighbor2.2.2.2update-sourceLoopback0
neighbor192.168.16.1remote-as1
!
address-familyipv4
network192.168.165.0
network192.168.166.0
neighbor2.2.2.2activate
neighbor2.2.2.2next-hop-self
neighbor192.168.16.1activate
exit-address-family
!
!
routerospf1
router-id6.6.6.6
network6.6.6.60.0.0.0area0
network192.168.26.00.0.0.7area0
!
!
!
iproute192.168.161.0255.255.255.0Loopback0
iproute192.168.162.0255.255.255.0Loopback0
!
!
linecon0
linevty010
privilegelevel15
login
passwordw
!
!
end
3.1.2.3 检验配置效果
C2
使用showipbgp可以看到125.0/126.0是源发路由,111.0/112.0/165.0/166.0是IBGP路由,131.0/132.0是EBGP路由。
使用showipospfdatabase可以看到,OSPF中没有外部路由。
C2#showipbgp
BGPtableversionis25,localrouterIDis2.2.2.2
Statuscodes:
ssuppressed,ddamped,hhistory,*valid,>best,i-internal,
rRIB-failure,SStale
Origincodes:
i-IGP,e-EGP,?
-incomplete
NetworkNextHopMetricLocPrfWeightPath
*>i192.168.111.06.6.6.6010001?
*>i192.168.112.06.6.6.6010001?
*>192.168.125.00.0.0.0032768i
*>192.168.126.00.0.0.0032768i
*>192.168.131.0192.168.23.2003?
*>192.168.132.0192.168.23.2003?
*>i192.168.165.06.6.6.601000i
*>i192.168.166.06.6.6.601000i
C2#showipospfdata
OSPFRouterwithID(2.2.2.2)(ProcessID1)
RouterLinkStates(Area0)
LinkIDADVRouterAgeSeq#ChecksumLinkcount
2.2.2.22.2.2.2910x800000090x00B6402
6.6.6.66.6.6.64980x800000040x00CD202
NetLinkStates(Area0)
LinkIDADVRouterAgeSeq#Checksum
192.168.26.22.2.2.2910x800000030x00C1CF
C2#
R1
使用showipbgp可以看到165.0/166.0是源发路由,125.0/126.0/131.0/132.0是IBGP路由,111.0/112.0是EBGP路由。
使用showipospfdatabase可以看到,OSPF中没有外部路由。
R1#showipbgp
BGPtableversionis9,localrouterIDis192.168.166.1
Statuscodes:
ssuppressed,ddamped,hhistory,*valid,>best,i-internal,
SStale
Origincodes:
i-IGP,e-EGP,?
-incomplete
NetworkNextHopMetricLocPrfPath
*>192.168.111.0192.168.16.101?
*>192.168.112.0192.168.16.101?
*>i192.168.125.02.2.2.20100i
*>i192.168.126.02.2.2.20100i
*>i192.168.131.02.2.2.201003?
*>i192.168.132.02.2.2.201003?
*>192.168.165.00.0.0.00i
*>192.168.166.00.0.0.00i
Totalnumberofprefixes8
R1#showipospfdata
OSPFRouterwithID(6.6.6.6)(ProcessID1)
RouterLinkStates(Area0.0.0.0)
LinkIDADVRouterAgeSeq#CkSumLinkcount
2.2.2.22.2.2.22540x800000090xb6402
6.6.6.66.6.6.66590x800000040xcd202
NetworkLinkStates(Area0.0.0.0)
LinkIDADVRouterAgeSeq#CkSum
192.168.26.22.2.2.22530x800000030xc1cf
4.1.2.4 重分发BGP的直连路由
C2
配置OSPF重分发BGP路由:
routerospf1
redistributebgp23subnets
使用showipospfdatabase可以看到EBGP路由(131.0/132.0)和直连路由(125.0/126.0)都重分发给OSPF,而IBGP路由没有重分发给OSPF。
因此可以看出Cisco会向下通告BGP的直连路由(这里是通过network命令配置的路由)。
C2#shoipospfdatabase
OSPFRouterwithID(2.2.2.2)(ProcessID1)
RouterLinkStates(Area0)
LinkIDADVRouterAgeSeq#ChecksumLinkcount
2.2.2.22.2.2.2140x8000000A0x00BA392
6.6.6.66.6.6.69310x800000040x00CD202
NetLinkStates(Area0)
LinkIDADVRouterAgeSeq#Checksum
192.168.26.22.2.2.25240x800000030x00C1CF
Type-5ASExternalLinkStates
LinkIDADVRouterAgeSeq#ChecksumTag
192.168.125.02.2.2.2130x800000010x00D6ED0
192.168.126.02.2.2.2130x800000010x00CBF70
192.168.131.02.2.2.2130x800000010x00CAF03
192.168.132.02.2.2.2130x800000010x00BFFA3
R1
配置OSPF重分发BGP路由:
routerospf1
redistributebgpsubnets
使用showipospfdatabase可以看到IBGP路由(125.0/126.0/131.0/132.0)和EBGP路由(111.0/112.0)都重分发给OSPF的,而这里没有直连路由(165.0/166.0)。
因为现在的实现中,BGP的直连路由是不下发的,因此重分发BGP路由的时候BGP的直连路由是不会被重分发的。
R1#shoipospfdatabase
OSPFRouterwithID(6.6.6.6)(ProcessID1)
RouterLinkStates(Area0.0.0.0)
LinkIDADVRouterAgeSeq#CkSumLinkcount
2.2.2.22.2.2.27810x800000110xa6482
6.6.6.66.6.6.690x800000140xb3282
NetworkLinkStates(Area0.0.0.0)
LinkIDADVRouterAgeSeq#CkSum
192.168.26.22.2.2.215440x800000080xb7d4
ASExternalLinkStates
LinkIDADVRouterAgeSeq#CkSumRouteTag
192.168.111.06.6.6.680x800000010xbc24E2192.168.111.0/240
192.168.112.06.6.6.680x800000010xb12eE2192.168.112.0/240
192.168.125.06.6.6.680x800000010x22b0E2