CCNP-31 BGP 1

简介:

CCNP-31 BGP 1

实验拓扑:

实验要求: R1 属于 AS 65500 中的一台路由器, R2-4 属于 AS 65000 中的路由器,在 AS 65000 中使用的事 OSPF 路由协议, R1 R2 配置成为 EBGP PEER R2 R4 之间配置成为 IBGP PEER
试验目的:掌握基本的 EBGP IBGP 的配置和传递路由需要的条件,能够使用 show debug 来解决简单的问题。

试验配置:
R1
R1(config)#int f0/0
R1(config-if)#ip add  10.1.1 .1 255.255.255.0
R1(config-if)#no shu
R1(config-if)#exit
R1(config)#int f1/0
R1(config-if)#exit
R1(config)#int f1/0
R1(config-if)#ip add 172.16.1.1 255.255.255.0
R1(config-if)#no shu
R1(config-if)#no keepalive
R1(config-if)#exit
 
R2
R2(config)#int f0/0
R2(config-if)#ip add  10.1.1 .2 255.255.255.0
R2(config-if)#no shu
R2(config-if)#exit
R2(config)#int f1/0
R2(config-if)#ip add 192.1.1.1 255.255.255.0
R2(config-if)#no shu
R2(config-if)#exit
R2(config)#int loop0
R2(config-if)#ip add  2.2.2 .2 255.255.255.0
R2(config-if)#exit
R2(config)#int loop1
R2(config-if)#ip add 172.16.2.1 255.255.255.0
R2(config-if)#no shu
R2(config-if)#exit
R2(config)#router ospf 100  
R2(config-router)#router-id  2.2.2 .2
R2(config-router)#network  0.0.0 .0 0.0. 0.0 a  0
R2(config-router)#exit
 
R3
R3(config)#int f1/0
R3(config-if)#ip add 192.1.1.2 255.255.255.0
R3(config-if)#no shu
R3(config-if)#exit
R3(config)#int f0/0
R3(config-if)#ip add 193.1.1.1 255.255.255.0
R3(config-if)#no shu
R3(config-if)#exit
R3(config)#int loop0
R3(config-if)#ip add  3.3.3 .3 255.255.255.0
R3(config-if)#exit
R3(config)#router ospf 100
R3(config-router)#router-id  3.3.3 .3
R3(config-router)#network  0.0.0 .0 0.0. 0.0 a  0
R3(config-router)#exit
 
R4
R4(config)#int f0/0
R4(config-if)#ip add 193.1.1.2 255.255.255.0
R4(config-if)#no shu
R4(config-if)#exit
R4(config)#int f1/0
R4(config-if)#ip add 172.16.3.1 255.255.255.0
R4(config-if)#no shu
R4(config-if)#no keepalive
R4(config-if)#exit
R4(config)#int loop0
R4(config-if)#ip add  4.4.4 .4 255.255.255.0
R4(config-if)#exit
R4(config)#router ospf 100
R4(config-router)#router-id  4.4.4 .4
R4(config-router)#network  0.0.0 .0 0.0. 0.0 a  0
R4(config-router)#exit
基本的链路层和 OSPF 配置完成了,上面用红色标记的部分是因为那个接口没有连接任何设备,我们用它来模拟内部网络,如果与接口没有活动的连接,那么接口就会 down 掉,使用 no keepalive 命令来取消检测活动连接,使之一直保持在 UP 状态。
下面我们开始 BGP 的配置,如下:
R1(config)#int loop0
R1(config-if)#ip add  1.1.1 .1 255.255.255.0//loopback 接口和 OSPF 中的作用一样,用作 router-id
R1(config-if)#exit
R1(config)#router bgp 65500  //65500 AS
R1(config-router)#neighbor  10.1.1 .2 remote-as 65000  // 指定邻居
R1(config-router)#network 172.16.1.0 mask 255.255.255.0  // 宣告网段
 
R2(config)#router bgp 65000
R2(config-router)#neighbor  10.1.1 .1 remote-as 65500
R2(config-router)#neighbor  4.4.4 .4 remote-as 65000
R2(config-router)#neighbor  4.4.4 .4 update-source loop0
R2(config-router)#network 192.1.1.0
R2(config-router)#network 172.16.2.0 mask 255.255.255.0
 
R4(config)#router bgp 65000
R4(config-router)#neighbor  2.2.2 .2 remote-as 65000
R4(config-router)#neighbor  2.2.2 .2 update-source loopback 0
R4(config-router)#network 172.16.3.0 mask 255.255.255.0
R4(config-router)#network 193.1.1.0
R4(config-router)#exit
BGP 的配置和其他路由协议差不多,也需要在全局模式下使用 router bgp xxx 命令,只不过后面的数字表示的是 AS 号, BGP 的邻居需要管理员人工指定,并且要表明邻居所在的 AS ,在 EBGP PEER 情况下, neighbor 后面的 ip 地址一般为直连的对端接口的 IP 地址,这是因为 BGP 有一个一跳的属性限制,可以修改,不过不建议这样做,不过在 IBGP PEER 的配置中, neighbor 后面的 ip 地址的要求就没有这么严格了,只要可达的 IP 地址都可以,在这里我们一般使用 LOOPBACK 接口的 IP 地址作为更新源,因为 loopback 接口有一个永远不会 down 的特性,并且在多条路经的时候,用 loopback 地址作为更新源地址可以实现冗余( BGP 不能实现负载均衡,他只选择最优的路径写入路由表!), update-source loopback 0 指明更新源为 loopback 口,这条命令需要在使用 loopback 接口作为更新源的对等体路由器都要配置!
最后使用 network 命令宣告需要发布的路由,这里 BGPv4 支持 VLSM CIDR ,所以 BGP 在更新一条路有的时候需要写出掩码,默认的是主网络的掩码,可以使用 mask 选项来配置掩码。
BGP EIGRP,OSPF,ISIS 一样都有三张表,邻居表, BGP 路由表和 IP 路由表,下面我们来看看 BGP 的邻居表:
R2#show ip bgp neighbors
BGP neighbor is  4.4.4 .4,  remote AS 65000, internal link  //IBGP 邻居
  BGP version 4, remote router ID  4.4.4 .4  //BGP 版本,邻居路由 ID
  BGP state = Established, up for 00:03:56  // 邻居状态 Established
  Last read 00:00:55, last write 00:00:55, hold time is 180, keepalive interval is 60 seconds
  Neighbor capabilities:
    Route refresh: advertised and received(old & new)
    Address family IPv4 Unicast: advertised and received
  Message statistics:
    InQ depth is 0
    OutQ depth is 0
                         Sent       Rcvd
    Opens:                  1          1
    Notifications:          0          0
    Updates:                2          2
    Keepalives:             6          6
    Route Refresh:          0          0
    Total:                  9          9
  Default minimum time between advertisement runs is 0 seconds
 
 For address family: IPv4 Unicast
  BGP table version 8, neighbor version 8/0
 Output queue size : 0
  Index 2, Offset 0, Mask 0x4
  2 update-group member
                                 Sent       Rcvd
  Prefix activity:               ----       ----
    Prefixes Current:               3          2 (Consumes 104 bytes)
    Prefixes Total:                 3          2
    Implicit Withdraw:              0          0
    Explicit Withdraw:              0          0
    Used as bestpath:             n/a          2
    Used as multipath:            n/a          0
 
                                   Outbound    Inbound
  Local Policy Denied Prefixes:    --------    -------
    Bestpath from this peer:              2        n/a
    Total:                                2          0
  Number of NLRIs in the update sent: max 2, min 1
 
  Connections established 1; dropped 0
  Last reset never
Connection state is ESTAB, I/O status: 1, unread input bytes: 0           
Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 255
Local host:  2.2.2 .2, Local port: 14692
Foreign host:  4.4.4 .4, Foreign port: 179
 
Enqueued packets for retransmit: 0, input: 0  mis-ordered: 0 (0 bytes)
 
Event Timers (current time is 0xF62D8):
Timer          Starts    Wakeups            Next
Retrans             6          0             0x0
TimeWait            0          0             0x0
AckHold             7          6             0x0
SendWnd             0          0             0x0
KeepAlive           0          0             0x0
GiveUp              0          0             0x0
PmtuAger            0          0             0x0
DeadWait            0          0             0x0
 
iss: 4085729406  snduna: 4085729684  sndnxt: 4085729684     sndwnd:  16107
irs:  975868670  rcvnxt:  975868940  rcvwnd:      16115  delrcvwnd:    269
 
SRTT: 178 ms, RTTO: 1209 ms, RTV: 1031 ms, KRTT: 0 ms
minRTT: 212 ms, maxRTT: 428 ms, ACK hold: 200 ms
Flags: active open, nagle
IP Precedence value : 6
 
Datagrams (max data segment is 536 bytes):
Rcvd: 8 (out of order: 0), with data: 7, total data bytes: 269
Sent: 15 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 7, total data bytes: 277
         
BGP neighbor is  10.1.1 .1,  remote AS 65500, external link  //EBGP 邻居
  BGP version 4, remote router ID  1.1.1 .1
  BGP state = Established, up for 00:05:00
  Last read 00:00:00, last write 00:00:00, hold time is 180, keepalive interval is 60 seconds
  Neighbor capabilities:
    Route refresh: advertised and received(old & new)
    Address family IPv4 Unicast: advertised and received
  Message statistics:
    InQ depth is 0
    OutQ depth is 0
                         Sent       Rcvd
    Opens:                  1          1
    Notifications:          0          0
    Updates:                3          1
    Keepalives:             7          7
    Route Refresh:          0          0
    Total:                 11          9
  Default minimum time between advertisement runs is 30 seconds
 
 For address family: IPv4 Unicast
  BGP table version 8, neighbor version 8/0
 Output queue size : 0
  Index 1, Offset 0, Mask 0x2
  1 update-group member
                                 Sent       Rcvd
  Prefix activity:               ----       ----
    Prefixes Current:               4          1 (Consumes 52 bytes)
    Prefixes Total:                 4          1
    Implicit Withdraw:              0          0
    Explicit Withdraw:              0          0
    Used as bestpath:             n/a          1
    Used as multipath:            n/a          0
 
                                   Outbound    Inbound
  Local Policy Denied Prefixes:    --------    -------
    Bestpath from this peer:              1        n/a
    Total:                                1          0
  Number of NLRIs in the update sent: max 2, min 1
 
  Connections established 1; dropped 0
  Last reset never
Connection state is ESTAB, I/O status: 1, unread input bytes: 0           
Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 1
Local host:  10.1.1 .2, Local port: 179
Foreign host:  10.1.1 .1, Foreign port: 14828
 
Enqueued packets for retransmit: 0, input: 0  mis-ordered: 0 (0 bytes)
 
Event Timers (current time is 0xF 658C ):
Timer          Starts    Wakeups            Next
Retrans            11          0             0x0
TimeWait            0          0             0x0
AckHold             9          2             0x0
SendWnd             0          0             0x0
KeepAlive           0          0             0x0
GiveUp              0          0             0x0
PmtuAger            0          0             0x0
DeadWait            0          0             0x0
 
iss:  300025546  snduna:  300025871  sndnxt:  300025871     sndwnd:  16060
irs: 1734736732  rcvnxt: 1734736963  rcvwnd:      16154  delrcvwnd:    230
 
SRTT: 251 ms, RTTO: 796 ms, RTV: 545 ms, KRTT: 0 ms
minRTT: 24 ms, maxRTT: 412 ms, ACK hold: 200 ms
Flags: passive open, nagle, gen tcbs
IP Precedence value : 6
 
Datagrams (max data segment is 1460 bytes):
Rcvd: 19 (out of order: 0), with data: 9, total data bytes: 230
Sent: 13 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 10, total data bytes: 324
以上为 R2 BGP 邻居信息,详细的说明了邻居的状态和一些参数。
(其他 BGP 路由器的邻居表略)
然后查看 BGP 路由表:
R1#show ip bgp
BGP table version is 6, local router ID is  1.1.1 .1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop            Metric LocPrf Weight Path
*> 172.16.1.0/24     0.0.0 .0                  0         32768 i
*> 172.16.2.0/24     10.1.1 .2                 0             0 65000 i
*> 172.16.3.0/24     10.1.1 .2                               0 65000 i
*> 192.1.1.0         10.1.1 .2                 0             0 65000 i
*> 193.1.1.0         10.1.1 .2                               0 65000 i
 
R2#show ip bgp
BGP table version is 8, local router ID is 172.16.2.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop            Metric LocPrf Weight Path
*> 172.16.1.0/24     10.1.1 .1                 0             0 65500 i
*> 172.16.2.0/24     0.0.0 .0                  0         32768 i
r>i172.16.3.0/24     4.4.4 .4                  0    100      0 i
*> 192.1.1.0         0.0.0 .0                  0         32768 i
r>i193.1.1.0         4.4.4 .4                  0    100      0 i
 
R4#show ip bgp
BGP table version is 7, local router ID is  4.4.4 .4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
 
   Network          Next Hop            Metric LocPrf Weight Path
*>i172.16.1.0/24     10.1.1 .1                 0    100      0 65500 i
*>i172.16.2.0/24     2.2.2 .2                  0    100      0 i
*> 172.16.3.0/24     0.0.0 .0                  0         32768 i
r>i192.1.1.0         2.2.2 .2                  0    100      0 i
*> 193.1.1.0         0.0.0 .0                  0         32768 i
上面的输出解释:
* 号表示存在的网络;
> 号表示最佳路径;
前面的 i 表示通过 IBGP 学到的路由;
前面的 r 表示写入到路由信息库失败的路由,可以通过命令 show ip bgp rib-failure 查看失败原因;
NextHop 表示下一跳;
Metric 用来表示 MED 属性;
LocPrf 用来表示本地优先级,默认为 100
Weight cisco 专有的一个属性,如果这条路由是自己产生的, Weight 32768 ,如果是从邻居学到的 Weight 0
Path BGP AS PATH 属性,用来表示经过的 AS
这里有的前面标记为 r 的原因是:在写入路由表的时候, ospf 同样也有到达该目的地的路由,所以管理距离小的就写入路由表 ,IBGP 的管理距离为 200 OSPF 的为 120 ,所以使用 OSPF 的路由。
BGP table version is 7 表示 BGP 的路由表经过了 7 次的交换和学习路由。
最后查看一下 IP 路由表:
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O -  OSPF IA  - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
      1.0.0 .0/24 is subnetted, 1 subnets
C        1.1.1 .0 is directly connected, Loopback0
     172.16.0.0/24 is subnetted, 3 subnets
C       172.16.1.0 is directly connected, FastEthernet1/0
B       172.16.2.0 [20/0] vi a 10.1.1 .2, 00:03:07
B       172.16.3.0 [20/0] vi a 10.1.1 .2, 00:02:25
      10.0.0 .0/24 is subnetted, 1 subnets
C        10.1.1 .0 is directly connected, FastEthernet0/0
B    193.1.1.0/24 [20/0] vi a 10.1.1 .2, 00:01:55
B    192.1.1.0/24 [20/0] vi a 10.1.1 .2, 00:03:07
 
R2#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O -  OSPF IA  - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
      2.0.0 .0/24 is subnetted, 1 subnets
C        2.2.2 .0 is directly connected, Loopback0
      3.0.0 .0/32 is subnetted, 1 subnets
O        3.3.3 .3 [110/2] via 192.1.1.2, 00:07:05, FastEthernet1/0
      4.0.0 .0/32 is subnetted, 1 subnets
O        4.4.4 .4 [110/3] via 192.1.1.2, 00:07:05, FastEthernet1/0
     172.16.0.0/24 is subnetted, 3 subnets
B       172.16.1.0 [20/0] vi a 10.1.1 .1, 00:04:15
C       172.16.2.0 is directly connected, Loopback1
O       172.16.3.0 [110/3] via 192.1.1.2, 00:07:05, FastEthernet1/0
      10.0.0 .0/24 is subnetted, 1 subnets
C        10.1.1 .0 is directly connected, FastEthernet0/0
O    193.1.1.0/24 [110/2] via 192.1.1.2, 00:07:05, FastEthernet1/0
C    192.1.1.0/24 is directly connected, FastEthernet1/0
 
R4#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O -  OSPF IA  - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
      2.0.0 .0/32 is subnetted, 1 subnets
O        2.2.2 .2 [110/3] via 193.1.1.1, 00:11:10, FastEthernet0/0
      3.0.0 .0/32 is subnetted, 1 subnets
O        3.3.3 .3 [110/2] via 193.1.1.1, 00:11:10, FastEthernet0/0
      4.0.0 .0/24 is subnetted, 1 subnets
C        4.4.4 .0 is directly connected, Loopback0
     172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
B       172.16.1.0/24 [200/0] vi a 10.1.1 .1, 00:07:52
B       172.16.2.0/24 [200/0] vi a 2.2.2 .2, 00:07:52
C       172.16.3.0/24 is directly connected, FastEthernet1/0
O       172.16.2.1/32 [110/3] via 193.1.1.1, 00:11:10, FastEthernet0/0
      10.0.0 .0/24 is subnetted, 1 subnets
O        10.1.1 .0 [110/3] via 193.1.1.1, 00:11:10, FastEthernet0/0
C    193.1.1.0/24 is directly connected, FastEthernet0/0
O    192.1.1.0/24 [110/2] via 193.1.1.1, 00:11:11, FastEthernet0/0
上面用红色标记的是从 BGP 学到的路由,下面我们来在 R4 ping 测试一下:
R4#p 172.16.1.1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
R4# p 10.1.1 .1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to  10.1.1 .1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 276/352/408 ms
R4# p 10.1.1 .2
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to  10.1.1 .2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 144/205/260 ms
R4#p 172.16.2.1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 168/245/356 ms
172.16.1.1 不通,为什么呢?我们 debug ip icmp 来观察一下:
R4#debug ip icmp
ICMP packet debugging is on
R4#p 172.16.1.1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:
U
*Mar  1 00:17:47.947: ICMP: dst (193.1.1.2) host unreachable rcv from 193.1.1.1.U
*Mar  1 00:17:50.051: ICMP: dst (193.1.1.2) host unreachable rcv from 193.1.1.1.U
Success rate is 0 percent (0/5)
R4#
*Mar  1 00:17:52.167: ICMP: dst (193.1.1.2) host unreachable rcv from 193.1.1.1
收到 193.1.1.1 的目标不可达错误消息,我们到 R3 上查看一下路由表:
R3#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O -  OSPF IA  - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
      2.0.0 .0/32 is subnetted, 1 subnets
O        2.2.2 .2 [110/2] via 192.1.1.1, 00:07:54, FastEthernet1/0
      3.0.0 .0/24 is subnetted, 1 subnets
C        3.3.3 .0 is directly connected, Loopback0
      4.0.0 .0/32 is subnetted, 1 subnets
O        4.4.4 .4 [110/2] via 193.1.1.2, 00:07:54, FastEthernet0/0
     172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
O       172.16.3.0/24 [110/2] via 193.1.1.2, 00:07:54, FastEthernet0/0
O       172.16.2.1/32 [110/2] via 192.1.1.1, 00:07:54, FastEthernet1/0
      10.0.0 .0/24 is subnetted, 1 subnets
O        10.1.1 .0 [110/2] via 192.1.1.1, 00:07:54, FastEthernet1/0
C    193.1.1.0/24 is directly connected, FastEthernet0/0
C    192.1.1.0/24 is directly connected, FastEthernet1/0
没有到 172.16.1.0/24 的路由,我们来添加一条静态路由:
Ip route 172.16.1.0 255.255.255.0 192.1.1.1
这样我们再到 R4 Ping 172.16.1.1 看看:
R4#p 172.16.1.1
 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 212/290/408 ms
通了。
其实在一个传输 AS 中,要求形成一个完全网格的拓扑,就是所有路由器必须都要直连在一起,以防止向在这里出现的中间有一台没有运行 BGP 的路由器所带来的问题。不过完全网格的限制可以通过其他的手段来解决。
下面我们再来观察一下 BGP 在建立邻居关系时候的 debug 信息:
R1#debug ip bgp ipv4 unicast
BGP debugging is on for address family: IPv4 Unicast
R1#clear ip bgp * 
R1#
*Mar  1 00:22:32.907: BGPNSF state:  10.1.1 .2 went from nsf_not_active to nsf_not_active
*Mar  1 00:22:32.907: BGP:  10.1.1 .2 went from Established to Idle  // 状态从 Established 变为 Idle
*Mar  1 00:22:32.907: %BGP-5-ADJCHANGE: neighbor  10.1.1 .2 Down User reset
*Mar  1 00:22:32.907: BGP:  10.1.1 .2 closing // 关闭邻居关系
*Mar  1 00:22:32.911: BGP:  10.1.1 .2 went from Idle to Active // 状态从 Idle 变为 Active
*Mar  1 00:22:32.919: BGP:  10.1.1 .2 open active, local address 10.1.1.1
*Mar  1 00:22:33.055: BGP:  10.1.1 .2 went from Active to OpenSent // 状态从 Active 变为 OpenSent
*Mar  1 00:22:33.055: BGP:  10.1.1 .2 sending OPEN, version 4, my as: 65500, holdtime 180 seconds // 发送 OPEN 消息
*Mar  1 00:22:33.063: BGP:  10.1.1 .2 send message type 1, length (incl. header) 45
*Mar  1 00:22:33.175: BGP:  10.1.1 .2 rcv message type 1, length (excl. header) 26
*Mar  1 00:22:33.175: BGP:  10.1.1 .2 rcv OPEN, version 4, holdtime 180 seconds // 收到 OPEN 消息
*Mar  1 00:22:33.179: BGP:  10.1.1 .2 rcv OPEN w/ OPTION parameter len: 16
*Mar  1 00:22:33.179: BGP:  10.1.1 .2 rcvd OPEN w/ optional parameter type 2 (Capability) len 6
*Mar  1 00:22:33.179: BGP:  10.1.1 .2 OPEN has CAPABILITY code: 1, length 4
*Mar  1 00:22:33.179: BGP:  10.1.1 .2 OPEN has MP_EXT CAP for afi/safi: 1/1
*Mar  1 00:22:33.179: BGP:  10.1.1 .2 rcvd OPEN w/ optional parameter type 2 (Capability) len 2
*Mar  1 00:22:33.183: BGP:  10.1.1 .2 OPEN has CAPABILITY code: 128, length 0
*Mar  1 00:22:33.183: BGP:  10.1.1 .2 OPEN has ROUTE-REFRESH capability(old) for all address-families
*Mar  1 00:22:33.183: BGP:  10.1.1 .2 rcvd OPEN w/ optional parameter type 2 (Capability) len 2
*Mar  1 00:22:33.183: BGP:  10.1.1 .2 OPEN has CAPABILITY code: 2, length 0
*Mar  1 00:22:33.183: BGP:  10.1.1 .2 OPEN has ROUTE-REFRESH capability(new) for all address-families
BGP:  10.1.1 .2 rcvd OPEN w/ remote AS 65000
*Mar  1 00:22:33.187: BGP:  10.1.1 .2 went from OpenSent to OpenConfirm// 状态从 OpenSent 变为 OpenConfirm
*Mar  1 00:22:33.187: BGP:  10.1.1 .2 went from OpenConfirm to Established// 状态从 OpenConfirm 变为 Established
 
从上面的 debug 信息我们可以看到 BGP 的邻居关系的形成经历了 Idle --Active--OpenSent--OpenConfirmEstablished 这些状态。

实验总结: 掌握基本的 BGP 配置,掌握 EBGP/IBGP PEER 配置中需要注意的问题和配置方法,并且掌握基本的查看和调试 BGP 信息和解决简单问题的方法。


















本文转自loveme2351CTO博客,原文链接: http://blog.51cto.com/loveme23/53577  ,如需转载请自行联系原作者





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