某局点SR8808-X设备关于 IPv6 BGP路由不通问题处理案例

1.8808上边设备8804的T2/2/2，8808与8804是EBGP。8808是AS65192，8804是AS65175
2.设备8808通过0/0/4口与6608的2/0/1口互联，属于AS65192。8808与SR6606内部ipv6 igp 使用ospfv3建立，业务路由发布使用bgp ipv6发布。

6608上的2/0/5.301子接口的ipv6地址240B:8054:6800:1::66/127， 访问不了8804的T2/2/2接口地址240B:8054:0:1::4018；6608设备接口改成126、125前缀的地址也是ping不通。
6608设备把2/0/5.301的接口地址改成前缀为128或者64的地址，可正常ping通8804的T2/2/2接口地址240B:8054:0:1::4018。
另外，现场反馈另外一个局点的使用的SR6616的设备，对应使用的是MIC插卡，同样的组网，使用127前缀地址均可以。
该局点对应接口使用的插卡是RT-SFE-L1  。

一、在66上使用127位的地址来ping测试8804的下联口地址，发现地址不通，在两端查看路由表路由都有，在8808上查看路由表和fib表项都正常
配置如下

[SDLY-SDZWW-YNX-SR6608-GigabitEthernet2/0/5.301]   //掩码127
#
interface GigabitEthernet2/0/5.301
description shenji-ipv6
vlan-type dot1q vid 301
ipv6 address 240B:8054:6800:1::66/127
#
return
[SDLY-SDZWW-YNX-SR6608-GigabitEthernet2/0/5.301]ping ipv6 -a 240B:8054:6800:1::66 240B:8054:0:1::4018  //ping测试
Ping6(56 data bytes) 240B:8054:6800:1::66 --> 240B:8054:0:1::4018, press CTRL_C to break
Request time out
Request time out
Request time out
Request time out
Request time out

--- Ping6 statistics for 240B:8054:0:1::4018 ---
5 packet(s) transmitted, 0 packet(s) received, 100.0% packet loss

<SDLY-SDZWW-YNX-SR6608>dis ipv6  routing-table 240B:8054:0:1::4018   //从6608上查看8804的路由
Summary count : 2

Destination: 240B:8054::/30                              Protocol  : BGP4+
NextHop    : 240B:8054:6800::                            Preference: 255
Interface  : GE2/0/1                                     Cost      : 0

Destination: 240B:8054:0:1::4018/127                     Protocol  : BGP4+
NextHop    : 240B:8054:6800::                            Preference: 255
Interface  : GE2/0/1                                     Cost      : 0

<SDLY-SDZWW-JQS-SR8804-B1>dis ipv6  routing-table  240B:8054:6800:1::66 //从8804上查看6608的路由
Summary count : 2

Destination: 240B:8054::/30                              Protocol  : BGP4+
NextHop    : 240B:8054::1                                Preference: 255
Interface  : XGE2/1/1                                    Cost      : 0

Destination: 240B:8054:6800::/40                         Protocol  : BGP4+
NextHop    : 240B:8054:0:1::4019                         Preference: 255
Interface  : XGE2/2/2                                    Cost      : 0

[SDLY-SDZWW-XXX-GYW-SR8808-01]dis ipv6 fib 240B:8054:6800:1::66      //8808上查看表项//当6608掩码为127为位时fib表项
Destination count: 1 FIB entry count: 1

Flag:
  U:Usable   G:Gateway   H:Host   B:Blackhole   D:Dynamic   S:Static
  R:Relay     F:FRR

Destination: 240B:8054:6800:1::66                           Prefix length: 127
Nexthop    : FE80::DEDA:80FF:FEFB:99BD                      Flags: UGR
Time stamp : 0x2e26                                         Label: Null
Interface  : GE0/0/4                                        Token: Invalid
[SDLY-SDZWW-XXX-GYW-SR8808-01]dis ipv6 routing-table 240B:8054:6800:1::66   //8808上查看表项//当6608掩码为127为位时路由表项
Summary count : 3

Destination: 240B:8054::/30                              Protocol  : BGP4+
NextHop    : 240B:8054:0:1::4018                         Preference: 255
Interface  : XGE2/0/5                                    Cost      : 0

Destination: 240B:8054:6800::/40                         Protocol  : Static
NextHop    : ::                                          Preference: 60
Interface  : NULL0                                       Cost      : 0

Destination: 240B:8054:6800:1::66/127                    Protocol  : BGP4+
NextHop    : 240B:8054:6800::7                           Preference: 255
Interface  : GE0/0/4                                     Cost      : 0

二、在66上使用128位的地址来ping测试8804的下联口地址，发现正常，在两端查看路由表路由都有，在8808上查看路由表和fib表项都正常
配置如下

[SDLY-SDZWW-YNX-SR6608-GigabitEthernet2/0/5.301]  //掩码128
#
interface GigabitEthernet2/0/5.301
description shenji-ipv6
vlan-type dot1q vid 301
ipv6 address 240B:8054:6800:1::66/128
#
return

[SDLY-SDZWW-YNX-SR6608-GigabitEthernet2/0/5.301]ping ipv6 -a 240B:8054:6800:1::66 240B:8054:0:1::4018 //ping测试
Ping6(56 data bytes) 240B:8054:6800:1::66 --> 240B:8054:0:1::4018, press CTRL_C to break
56 bytes from 240B:8054:0:1::4018, icmp_seq=0 hlim=63 time=8.326 ms
56 bytes from 240B:8054:0:1::4018, icmp_seq=1 hlim=63 time=7.986 ms
56 bytes from 240B:8054:0:1::4018, icmp_seq=2 hlim=63 time=7.664 ms
56 bytes from 240B:8054:0:1::4018, icmp_seq=3 hlim=63 time=8.332 ms
56 bytes from 240B:8054:0:1::4018, icmp_seq=4 hlim=63 time=8.323 ms

--- Ping6 statistics for 240B:8054:0:1::4018 ---
5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss
round-trip min/avg/max/std-dev = 7.664/8.126/8.332/0.266 ms
<SDLY-SDZWW-YNX-SR6608>dis ipv6  routing-table 240B:8054:0:1::4018   //从6608上查看8804的路由
Summary count : 2

Destination: 240B:8054::/30                              Protocol  : BGP4+
NextHop    : 240B:8054:6800::                            Preference: 255
Interface  : GE2/0/1                                     Cost      : 0

Destination: 240B:8054:0:1::4018/127                     Protocol  : BGP4+
NextHop    : 240B:8054:6800::                            Preference: 255
Interface  : GE2/0/1                                     Cost      : 0

<SDLY-SDZWW-JQS-SR8804-B1>dis ipv6  routing-table  240B:8054:6800:1::66 //从8804上查看6608的路由
Summary count : 2

Destination: 240B:8054::/30                              Protocol  : BGP4+
NextHop    : 240B:8054::1                                Preference: 255
Interface  : XGE2/1/1                                    Cost      : 0

Destination: 240B:8054:6800::/40                         Protocol  : BGP4+
NextHop    : 240B:8054:0:1::4019                         Preference: 255
Interface  : XGE2/2/2                                    Cost      : 0
[SDLY-SDZWW-XXX-GYW-SR8808-01]dis ipv6 routing-table 240B:8054:6800:1::66    //8808上查看表项//当6608掩码为128为位时路由表项
Summary count : 3

Destination: 240B:8054::/30                              Protocol  : BGP4+
NextHop    : 240B:8054:0:1::4018                         Preference: 255
Interface  : XGE2/0/5                                    Cost      : 0

Destination: 240B:8054:6800::/40                         Protocol  : Static
NextHop    : ::                                          Preference: 60
Interface  : NULL0                                       Cost      : 0

Destination: 240B:8054:6800:1::66/128                    Protocol  : BGP4+
NextHop    : 240B:8054:6800::7                           Preference: 255
Interface  : GE0/0/4                                     Cost      : 0
[SDLY-SDZWW-XXX-GYW-SR8808-01]

[SDLY-SDZWW-XXX-GYW-SR8808-01]dis ipv6 fib 240B:8054:6800:1::66   //8808上查看表项//当6608掩码为128为位时fib表项
Destination count: 1 FIB entry count: 1

Flag:
  U:Usable   G:Gateway   H:Host   B:Blackhole   D:Dynamic   S:Static
  R:Relay     F:FRR

Destination: 240B:8054:6800:1::66                           Prefix length: 128
Nexthop    : FE80::DEDA:80FF:FEFB:99BD                      Flags: UGHR
Time stamp : 0x2e28                                         Label: Null
Interface  : GE0/0/4                                        Token: Invalid

三、通过流统发现，当掩码为127位时，在8808这台硬转设备上丢了，     丢的原因是硬件资源不足了，导致fib没有下发成功：

debug ipv4-drv show config slot 0

**********************************************************
- IPv4 Config   Slot 0
**********************************************************
- ARP SIZE:             16384
- ArpCanNotSetToHW:     NO
- IPV4 ROUTE SIZE:      65536
- ECMP SIZE:            8
- ND SIZE:              8192
- IPV6 ROUTE SIZE:      8192
- IPV6 LongPrefRT:      128----------------一共128个资源，掩码65~127范围的会申请这个。
- VLAN INTF MODE:       2
- NH SIZE:              16384

debug ipv6-drv show statistics slot 0

**********************************************************
- IPv6 Statistics       Slot 0
**********************************************************
- ROUTE TOTAL COUNT:            0
- ROUTE LongPref COUNT:         128-------------ipv6已经用了128 了，用满了。
- ROUTE DMAFAIL COUNT:          0
- ECMP ROUTE COUNT:             0
- ECMP DMAFAIL COUNT:           0
- Linklocal-ND COUNT:           0
- ND-ACL COUNT:                 0
- IPV6 Plat ND Demand NUM:      1340
- IPV6 ND Successed NUM:        1305
- IPV6 Plat Route Demand NUM:   17362799
- IPV6 Route Successed NUM:     46287

1、 需要转发通的业务，路由前缀采用64位掩码或者128位掩码。
2、 将当前板卡更换成spe板卡。