组网说明:
问题描述:
S12510X交换机通过三层物理接口与多台我司交换机建立ospf邻居,如S10508交换机等:
1. IMC服务器上提示告警:S12510X交换机上存在大量router id 10.72.1.9 冲突,在S12510X交换机上打开debug ospf event error开关,router-id冲突日志如下:
*Oct 17 14:15:15:602 2016 H3C OSPF/7/DEBUG: -MDC=1;
OSPF 1 :OSPF received packet having conflicted Router ID :10.72.1.9.
*Oct 17 14:15:21:606 2016 H3C OSPF/7/DEBUG: -MDC=1;
OSPF 1 :OSPF received packet having conflicted Router ID :10.72.1.9.
2. 现场ospf邻居没有震荡,路由学习均正常;
1、 通过display ospf statistics error查看ospf错包统计信息,Router ID confusion存在计数,且通过上述命令多次查看,冲突计数是不断增加的;正常情况下,可基本判断上述冲突是直连设备router-id冲突导致的,因为只有直连router-id冲突才会导致ospf错包统计中的Router ID confusion存在计数且不断增加,但从现场反馈的情况看,S125x交换机与其他设备的ospf邻居一直是稳定的,且邻居数量也正确,由此判断现网很有可能是存在环路,故而导致自己发出的hello报文自己又收到了;ospf错误统计报文信息见下:
===================================================
===============display ospf statistics error===============
OSPF Process 1 with Router ID 10.72.1.9
OSPF Packet Error Statistics
1487 : Router ID confusion 0 : Bad packet
0 : Bad version 0 : Bad checksum
0 : Bad area ID 0 : Drop on unnumbered link
0 : Bad virtual link 0 : Bad authentication type
0 : Bad authentication key 0 : Packet too small
0 : Neighbor state low 0 : Transmit error
3 : Interface down 0 : Unknown neighbor
2、 从现场反馈的debug ospf packet信息看,每当S125x设备从10.73.1.177/10.73.1.185这两个源IP所对应的接口发出hello报文时,日志都会提示设备收到router-id冲突报文,但是从其他接口发出的报文都无此情况,且上述两接口发出的报文的内容也存在一定的差异,比如正常报文中携带的邻居id,故而怀疑现场上述两个接口存在打环情况;现场debug信息见下:
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; OSPF 1: Sending packets.
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Source address: 10.73.1.177
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Destination address: 224.0.0.5
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Version 2, Type: 1, Length: 44.
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Router: 10.72.1.9, Area: 0.0.0.0, Checksum: 58459.
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Authentication type: 00, Key(ASCII): 0 0 0 0 0 0 0 0.
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Network mask: 255.255.255.248, Hello interval: 10, Option: _E_.
*Oct 17 14:15:45:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Router priority: 1, Dead Interval: 40, DR: 10.73.1.177, BDR: 0.0.0.0.
*Oct 17 14:15:45:602 2016 H3C OSPF/7/DEBUG: -MDC=1;
OSPF 1 :OSPF received packet having conflicted Router ID :10.72.1.9.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; OSPF 1: Sending packets.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Source address: 10.73.1.97
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Destination address: 224.0.0.5
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Version 2, Type: 1, Length: 48.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Router: 10.72.1.9, Area: 0.0.0.0, Checksum: 52514.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Authentication type: 00, Key(ASCII): 0 0 0 0 0 0 0 0.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Network mask: 255.255.255.248, Hello interval: 10, Option: _E_.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Router priority: 1, Dead Interval: 40, DR: 10.73.1.98, BDR: 10.73.1.97.
*Oct 17 14:15:46:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Neighbor ID: 10.73.1.145.
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; OSPF 1: Sending packets.
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Source address: 10.73.1.185
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Destination address: 224.0.0.5
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Version 2, Type: 1, Length: 44.
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Router: 10.72.1.9, Area: 0.0.0.0, Checksum: 58451.
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Authentication type: 00, Key(ASCII): 0 0 0 0 0 0 0 0.
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Network mask: 255.255.255.248, Hello interval: 10, Option: _E_.
*Oct 17 14:16:01:601 2016 H3C OSPF/7/DEBUG: -MDC=1; Router priority: 1, Dead Interval: 40, DR: 10.73.1.185, BDR: 0.0.0.0.
*Oct 17 14:16:01:602 2016 H3C OSPF/7/DEBUG: -MDC=1;
OSPF 1 :OSPF received packet having conflicted Router ID :10.72.1.9.
3、 让现场shutdown关闭上述两个IP对应的两个出接口中的一个接口GigabitEthernet1/8/0/4,设备上router-id冲突日志马上消失,现场关闭另外一个接口亦是如此,由此进一步可确认了现场组网存在环路的可能性;经现场排查,S125X交换机分别通过G1/8/0/4接口和G2/8/0/4接口与S105交换机建立OSPF邻居,G1/8/0/4接口和G2/8/0/4接口均为三层接口,但是S125x交换机和S105交换机之间串着一台二层傻瓜防火墙,其部署方式为纯二层透传,故而导致G1/8/0/4发出的hello报文又从G2/8/0/4接口收到,反之如此,以致设备一直报ospf router-id冲突;
#
interface GigabitEthernet1/8/0/4
port link-mode route
ip address 10.73.1.177 255.255.255.248
pim sm
#
#
interface GigabitEthernet2/8/0/4
port link-mode route
ip address 10.73.1.185 255.255.255.248
pim sm
#
建议现场对S125X和S105交换机之间串接的防火墙进行精细的vlan隔离部署;
1、 OSPF组网中时常会出现OSPF Router ID配置冲突的问题,上述组网在实际项目部署中是非常常见的,也是目前遇见过最多的导致ospf router-id冲突产生的组网,处理此类问题的时候,建议现场摸清组网环境,按照上述步骤,逐一进行排查处理;
2、 在项目部署过程中,建议OSPF Router ID在配置OSPF进程前,规划好每台路由器的Router ID,比如专门划出一个网段作为ospf router-id使用,并通过使用ospf 1 router-id X.X.X.X 命令为每一个OSPF进程手工指定好Router ID;
3、 如果是在启动OSPF进程后再指定或更改Router ID,一定要在用户视图下重启OSPF进程以保证新Router ID生效;如果在修改router-id后未进行ospf进程重启,若修改前的router-id与其他设备存在冲突,则冲突会一直存在,此时则建议重启修改ospf router-id侧的ospf进程。
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