用bgpcommunity属性实现路由的双路备份

用户有两个网络6.6.6.0和7.7.7.0，
要求：所有访问6网络的数据都通过RTB到RTA，所有访问7.7.7.0的数据都走RTC到RTA，并且互相备份；
实现：通过路由策略在RTA向RTB和RTC通告这两个路由的时候分别赋予不同的community属性，然后在RTB和RTC上通过community属性设置路由的本地优先属性从而达到客户的要求；
[RTA]display current-configuration
Now create configuration...
Current configuration
!
version 1.74
sysname RTA
firewall enable
aaa-enable
aaa accounting-scheme optional
!
acl 100 match-order auto
rule normal permit ip source 6.6.6.0 0.0.0.255 destination any
rule normal deny ip source any destination any
!
acl 110 match-order auto
rule normal permit ip source 7.7.7.0 0.0.0.255 destination any
rule normal deny ip source any destination any
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
!
interface Serial0
clock DTECLK1
link-protocol ppp
ip address 10.1.0.1 255.255.255.0
!
interface Serial1
link-protocol ppp
ip address 10.2.0.1 255.255.255.0
!
interface LoopBack1
ip address 6.6.6.1 255.255.255.0
!
interface LoopBack2
ip address 7.7.7.1 255.255.255.0
!
quit
bgp 100
undo synchronization
network 6.6.6.0 mask 255.255.255.0
network 7.7.7.0 mask 255.255.255.0
peer 10.1.0.2 as-number 200
peer 10.1.0.2 route-policy for6 eXPort
peer 10.1.0.2 advertise-community
peer 10.2.0.2 as-number 200
peer 10.2.0.2 route-policy for7 export
peer 10.2.0.2 advertise-community
!
quit
!
quit
route-policy for6 permit 10
if-match ip address 100
apply community 100:1
quit
route-policy for6 permit 20
if-match ip address 110
apply community 200:1
quit
route-policy for7 permit 10
if-match ip address 100
apply community 200:1
quit
route-policy for7 permit 20
if-match ip address 110
apply community 100:1
!
return
[RTA]dis ip rou
Routing Tables:
Destination/Mask　ProtoPref Metric NexthopInterface
6.6.6.0/24　Direct0 0　6.6.6.1 LoopBack1
6.6.6.1/32　Direct0 0127.0.0.1 LoopBack0
7.7.7.0/24　Direct0 0　7.7.7.1 LoopBack2
7.7.7.1/32　Direct0 0127.0.0.1 LoopBack0
10.1.0.0/24　Direct0 0 10.1.0.2 Serial0
10.1.0.1/32　Direct0 0127.0.0.1 LoopBack0
10.1.0.2/32　Direct0 0 10.1.0.2 Serial0
10.2.0.0/24　Direct0 0 10.2.0.2 Serial1
10.2.0.1/32　Direct0 0127.0.0.1 LoopBack0
10.2.0.2/32　Direct0 0 10.2.0.2 Serial1
127.0.0.0/8Direct0 0127.0.0.1 LoopBack0
127.0.0.1/32　Direct0 0127.0.0.1 LoopBack0
[RTA]
[RTA]dis bgp su
PeerStateversion ASMsg-RxMsg-TxQueued-Tx Up/Down
10.1.0.2Established 420035290　00:24:42
10.2.0.2Established 420035290　00:24:43
[RTA]
[RTA]
[RTB]
[RTB]display current-configuration
Now create configuration...
Current configuration
!
version 1.74
sysname RTB
firewall enable
aaa-enable
aaa accounting-scheme optional
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
!
interface Serial0
link-protocol ppp
!
interface Serial1
link-protocol ppp
ip address 10.1.0.2 255.255.255.0
!
interface Serial2
clock DTECLK1
link-protocol ppp
ip address 10.3.0.1 255.255.255.0
ospf enable area 0.0.0.0
!
interface Serial3
link-protocol ppp
!
quit
ospf enable
!
quit
!
bgp 200
undo synchronization
network 10.1.0.0 mask 255.255.255.0
peer 10.3.0.2 as-number 200
peer 10.4.0.1 as-number 200
peer 10.1.0.1 as-number 100
peer 10.1.0.1 route-policy for6_7 import
!
quit
!
quit
route-policy for6_7 permit 10
if-match community 1
apply local-preference 400
quit
route-policy for6_7 permit 20
if-match community 2
apply local-preference 300
!
quit
ip community-list 1　permit 100:1
ip community-list 2　permit 200:1
!
return
[RTB]dis bgp su
PeerStateversion ASMsg-RxMsg-TxQueued-Tx Up/Down
10.3.0.2Established 420022330　00:21:03
10.4.0.1Established 42007 8 0　00:01:08
10.1.0.1Established 410027360　00:24:55
[RTB]dis bgp
router ID: 10.3.0.1
Flags:# - valid^ - best
D - damped　H - history
I - internalS - aggregate suppressed
Destination/MaskNext HopFlags　MedLocPref Origin Path
6.6.6.0/2410.1.0.1 #^400IGP100
7.7.7.0/2410.2.0.1 #^I　400IGP100
10.1.0.1 #300IGP100
10.1.0.0/240.0.0.0　#^　IGP
10.2.0.0/2410.4.0.1 #^I　100IGP
[RTB]display ip routing-table
Routing Tables:
Destination/Mask　ProtoPref Metric NexthopInterface
6.6.6.0/24 BGP　170 0 10.1.0.1 Serial1
7.7.7.0/24 BGP　170 0 10.2.0.1 Serial2
10.1.0.0/24　Direct0 0 10.1.0.1 Serial1
10.1.0.1/32　Direct0 0 10.1.0.1 Serial1
10.1.0.2/32　Direct0 0127.0.0.1 LoopBack0
10.2.0.0/24 BGP　170 0 10.4.0.1 Serial2
10.3.0.0/24　Direct0 0 10.3.0.2 Serial2
10.3.0.1/32　Direct0 0127.0.0.1 LoopBack0
10.3.0.2/32　Direct0 0 10.3.0.2 Serial2
10.4.0.0/24OSPF10　3124 10.3.0.2 Serial2
127.0.0.0/8Direct0 0127.0.0.1 LoopBack0
127.0.0.1/32　Direct0 0127.0.0.1 LoopBack0
[RTB]
[RTC-bgp]
[RTC-bgp]qu
[RTC]
[RTC]display current-configuration
Now create configuration...
Current configuration
!
version 1.74
sysname RTC
firewall enable
aaa-enable
aaa accounting-scheme optional
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
!
interface Serial0
clock DTECLK1
link-protocol ppp
ip address 10.4.0.1 255.255.255.0
ospf enable area 0.0.0.0
!
interface Serial1
clock DTECLK1
link-protocol ppp
ip address 10.2.0.2 255.255.255.0
!
quit
ospf enable
!
quit
!
bgp 200
undo synchronization
network 10.2.0.0 mask 255.255.255.0
peer 10.2.0.1 as-number 100
peer 10.2.0.1 route-policy for6_7 import
peer 10.4.0.2 as-number 200
peer 10.3.0.1 as-number 200
!
quit
!
quit
route-policy for6_7 permit 10
if-match community 1
apply local-preference 200
quit
route-policy for6_7 permit 20
if-match community 2
apply local-preference 400
!
quit
ip community-list 1　permit 200:1
ip community-list 2　permit 100:1
!
return
[RTC]dis bgp
router ID: 10.2.0.2
Flags:# - valid^ - best
D - damped　H - history
I - internalS - aggregate suppressed
Destination/MaskNext HopFlags　MedLocPref Origin Path
6.6.6.0/2410.1.0.1 #^I　400IGP100
10.2.0.1 #200IGP100
7.7.7.0/2410.2.0.1 #^400IGP100
10.1.0.0/2410.3.0.1 #^I　100IGP
10.2.0.0/240.0.0.0　#^　IGP
[RTC]display ip routing-table
Routing Tables:
Destination/Mask　ProtoPref Metric NexthopInterface
6.6.6.0/24 BGP　170 0 10.1.0.1 Serial0
7.7.7.0/24 BGP　170 0 10.2.0.1 Serial1
10.1.0.0/24 BGP　170 0 10.3.0.1 Serial0
10.2.0.0/24　Direct0 0 10.2.0.1 Serial1
10.2.0.1/32　Direct0 0 10.2.0.1 Serial1
10.2.0.2/32　Direct0 0127.0.0.1 LoopBack0
10.3.0.0/24OSPF10　3124 10.4.0.2 Serial0
10.4.0.0/24　Direct0 0 10.4.0.2 Serial0
10.4.0.1/32　Direct0 0127.0.0.1 LoopBack0
10.4.0.2/32　Direct0 0 10.4.0.2 Serial0
127.0.0.0/8Direct0 0127.0.0.1 LoopBack0
127.0.0.1/32　Direct0 0127.0.0.1 LoopBack0
[RTC]
[RTC]
//路由器D没有任何非凡配置，只是bgp的
基本配置，所以配置省略：
[RTD]
[RTD]dis bgp
^
% Incomplete command found at "^" position.
[RTD]dis bgp r
[RTD]dis bgp routing-table
Flags:# - valid^ - active　I - internal
D - damped　H - history S - aggregate suppressed
Dest/Mask　Next-hopMedLocal-pref Origin As-path
---------------------------------------------------------------------------
#^I 6.6.6.0/24 10.1.0.10　400 IGP100
#^I 7.7.7.0/24 10.2.0.10　400 IGP100
#^I 10.1.0.0/2410.3.0.10　100 IGP
#^I 10.2.0.0/2410.4.0.10　100 IGP
Routes total: 4
[RTD]
[RTD]dis ip rou
Routing Table: public net
Destination/MaskProtocol Pre　CostNexthop Interface
6.6.6.0/24 BGP　256　010.1.0.1Serial3/1
7.7.7.0/24 BGP　256　010.2.0.1Serial3/0
10.1.0.0/24BGP　256　010.3.0.1Serial3/1
10.2.0.0/24BGP　256　010.4.0.1Serial3/0
10.3.0.0/24DIRECT0010.3.0.2Serial3/1
10.3.0.1/32DIRECT0010.3.0.1Serial3/1
10.3.0.2/32DIRECT00127.0.0.1InLoopBack0
10.4.0.0/24DIRECT0010.4.0.2Serial3/0
10.4.0.1/32DIRECT0010.4.0.1Serial3/0
10.4.0.2/32DIRECT00127.0.0.1InLoopBack0
127.0.0.0/8DIRECT00127.0.0.1InLoopBack0
127.0.0.1/32DIRECT00127.0.0.1InLoopBack0
[RTD]
[RTD]
[RTD]dis bgp pe
[RTD]dis bgp peer
PeerAS-num Ver Queued-TxMsg-RxMsg-TxUp/Down　State
--------------------------------------------------------------------------------
10.3.0.1　200　4　0 31 2400:21:42 Established
10.4.0.1　200　4　0 35 2500:22:07 Established
[RTD]