BGP Lab RR & Loop (1)
Topology:
R3,R4为Route Reflector。
R2,R5为客户。
实验目的：理解RR的冗余设计。
Platform:cisco iou
Step 1、配置各台路由器的IP地址，并且使用Ping命令确认各路由器的直连口的互通性。
Step 2、load config file (basic_config.txt)
Step 3、R3和R4上的相关RR配置。
R3:
router bgp 2
neighbor 5.5.5.5 route-reflector-client
neighbor 2.2.2.2 route-reflector-client
R4:
router bgp 2
neighbor 2.2.2.2 route-reflector-client
neighbor 5.5.5.5 route-reflector-client
配置完以后
可以观察出R4收到1.1.1.1的路由来自R3，R2
当R3，R4配置在同一个簇后观察。
R3,R4:
router bgp 2
bgp cluster-id 34.34.34.34
结论：
当一个AS中包含的IBGP对等体太多时，配置全互联就比较麻烦，这时候可以起路由反射器。
将一个路由器配置成路由反射器（RR），其他的IBGP路由器当做客户，这些客户只与RR建立对等体关系，而不是与另外的每个路由器对等。（可以大大的减少配置）
反射规则：
1）如果路由是从非客户过来则反射给客户，不会给非客户。
2）如果路由是从客户过来，会反射给客户和非客户。
3）如果路由是从EBGP邻居过来，反射给客户和非客户。
为了节省开销，当在同一个区域时，两个RR中通过指定同一个cluster-id，可以节省内存存放学过来的路由条目，因为缺省情况下，一个RR就是一个cluster，这个两个RR之间相互发放路由，就多出一倍，如果将两个RR同指定为一个cluster后，就可以减少开销。
R1++++++++++++++++++++++++++++++++++++++++++++++++++++
int lo 0
ip add 1.1.1.1 255.255.255.255
int e0/0
no sh
int e0/0.12
en do 12
ip add 12.1.1.1 255.255.255.0
router bgp 1
no synchronization
bgp router-id 1.1.1.1
bgp log-neighbor-changes
network 1.1.1.1 mask 255.255.255.255
neighbor 12.1.1.2 remote-as 2
no auto-summary
R2++++++++++++++++++++++++++++++++++++++++++++++
int lo 0
ip add 2.2.2.2 255.255.255.255
int e0/0
no sh
int e0/0.12
en do 12
ip add 12.1.1.2 255.255.255.0
int e0/0.24
en do 24
ip add 24.1.1.2 255.255.255.0
int e0/0.23
en do 23
ip add 23.1.1.2 255.255.255.0
router ospf 100
router-id 2.2.2.2
log-adjacency-changes
network 2.2.2.2 0.0.0.0 area 0
network 23.1.1.0 0.0.0.255 area 0
network 24.1.1.0 0.0.0.255 area 0
!
router bgp 2
no synchronization
bgp router-id 2.2.2.2
bgp log-neighbor-changes
neighbor 3.3.3.3 remote-as 2
neighbor 3.3.3.3 update-source Loopback0
neighbor 3.3.3.3 next-hop-self
neighbor 4.4.4.4 remote-as 2
neighbor 4.4.4.4 update-source Loopback0
neighbor 4.4.4.4 next-hop-self
neighbor 12.1.1.1 remote-as 1
no auto-summary
R3+++++++++++++++++++++++++++++++++++++++++++++++++++++
int lo 0
ip add 3.3.3.3 255.255.255.255
int e0/0
no sh
int e0/0.23
en do 23
ip add 23.1.1.3 255.255.255.0
int e0/0.34
en do 34
ip add 34.1.1.3 255.255.255.0
int e0/0.35
en do 35
ip add 35.1.1.3 255.255.255.0
router ospf 100
net 0.0.0.0 0.0.0.0 a 0
router bgp 2
no synchronization
bgp router-id 3.3.3.3
bgp log-neighbor-changes
neighbor 2.2.2.2 remote-as 2
neighbor 2.2.2.2 update-source Loopback0
neighbor 2.2.2.2 next-hop-self
neighbor 4.4.4.4 remote-as 2
neighbor 4.4.4.4 update-source Loopback0
neighbor 4.4.4.4 next-hop-self
neighbor 5.5.5.5 remote-as 2
neighbor 5.5.5.5 update-source Loopback0
neighbor 5.5.5.5 next-hop-self
no auto-summary
R4++++++++++++++++++++++++++++++++++++++++++++++++++++++++
int lo 0
ip add 4.4.4.4 255.255.255.255
int e0/0
no sh
int e0/0.34
en do 34
ip add 34.1.1.4 255.255.255.0
int e0/0.24
en do 24
ip add 24.1.1.4 255.255.255.0
int e0/0.45
en do 45
ip add 45.1.1.4 255.255.255.0
router ospf 100
net 0.0.0.0 0.0.0.0 a 0
router bgp 2
no synchronization
bgp router-id 4.4.4.4
bgp log-neighbor-changes
neighbor 2.2.2.2 remote-as 2
neighbor 2.2.2.2 update-source Loopback0
neighbor 2.2.2.2 next-hop-self
neighbor 3.3.3.3 remote-as 2
neighbor 3.3.3.3 update-source Loopback0
neighbor 3.3.3.3 next-hop-self
neighbor 5.5.5.5 remote-as 2
neighbor 5.5.5.5 update-source Loopback0
neighbor 5.5.5.5 next-hop-self
no auto-summary
R5++++++++++++++++++++++++++++++++++++++++++++++++++++++
int lo 0
ip add 5.5.5.5 255.255.255.255
int e0/0
no sh
int e0/0.35
en do 35
ip add 35.1.1.5 255.255.255.0
int e0/0.45
en do 45
ip add 45.1.1.5 255.255.255.0
router ospf 100
net 0.0.0.0 0.0.0.0 a 0
router bgp 2
no synchronization
bgp router-id 5.5.5.5
bgp log-neighbor-changes
network 5.5.5.5 mask 255.255.255.255
neighbor 3.3.3.3 remote-as 2
neighbor 3.3.3.3 update-source Loopback0
neighbor 3.3.3.3 next-hop-self
neighbor 4.4.4.4 remote-as 2
neighbor 4.4.4.4 update-source Loopback0
neighbor 4.4.4.4 next-hop-self
no auto-summary
