S9850 PING failure with 128 mask IPv6 address
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Network Topology
[server]---[H3c]<---bgp--->[spine]<---bgp--->[leaf]-Loopback20
ping from [server] to loopback20 of [leaf]
Problem Description
Customer feedback that PING is not reachable when host IPv6 address is configured to this loopback interface with mask 128.
But it works normally when we config IPv6 address with mask 64.
Here is the configs on loopback20 of [leaf]
#
interface LoopBack20
ipv6 enable
ipv6 address 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128
#
But server can't ping 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
ping6 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
PING 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1(2a03:6b9:fc00:1f80:6b9:fc00:1f80:1) 56 data bytes
^C
--- 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 ping statistics ---
26 packets transmitted, 0 received, 100% packet loss, time 24999ms
Process Analysis
We check the ipv6 routing table and fib table, but everything is fine.
When the mask is 128:
<lab-kr-6s98>display ipv6 routing-table 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
Summary count : 8
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::101:1:C2 Preference: 255
Interface : HGE1/0/25.101 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::102:1:C2 Preference: 255
Interface : HGE1/0/25.102 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::103:1:C2 Preference: 255
Interface : HGE1/0/25.103 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::104:1:C2 Preference: 255
Interface : HGE1/0/25.104 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::105:1:C2 Preference: 255
Interface : HGE1/0/25.105 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::106:1:C2 Preference: 255
Interface : HGE1/0/25.106 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::107:1:C2 Preference: 255
Interface : HGE1/0/25.107 Cost : 0
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1/128 Protocol : BGP4+
NextHop : FE80::108:1:C2 Preference: 255
Interface : HGE1/0/25.108 Cost : 0
<lab-kr-6s98>display ipv6 fib 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
Destination count: 1 FIB entry count: 8
Flag:
U:Useable G:Gateway H:Host B:Blackhole D:Dynamic S:Static
R:Relay F:FRR
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::101:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.101 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::102:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.102 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::103:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.103 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::104:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.104 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::105:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.105 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::106:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.106 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::107:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.107 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1 Prefix length: 128
Nexthop : FE80::108:1:C2 Flags: UGH
Time stamp : 0xb5e2 Label: Null
Interface : HGE1/0/25.108 Token: Invalid
When the mask is 64 :
[lab-kr-6s98-probe]display ipv6 routing-table 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
Summary count : 8
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::101:1:C2 Preference: 255
Interface : HGE1/0/25.101 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::102:1:C2 Preference: 255
Interface : HGE1/0/25.102 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::103:1:C2 Preference: 255
Interface : HGE1/0/25.103 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::104:1:C2 Preference: 255
Interface : HGE1/0/25.104 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::105:1:C2 Preference: 255
Interface : HGE1/0/25.105 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::106:1:C2 Preference: 255
Interface : HGE1/0/25.106 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::107:1:C2 Preference: 255
Interface : HGE1/0/25.107 Cost : 0
Destination: 2A03:6B9:FC00:1F80::/64 Protocol : BGP4+
NextHop : FE80::108:1:C2 Preference: 255
Interface : HGE1/0/25.108 Cost : 0
[lab-kr-6s98-probe]display ipv6 fib 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
Destination count: 1 FIB entry count: 8
Flag:
U:Useable G:Gateway H:Host B:Blackhole D:Dynamic S:Static
R:Relay F:FRR
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::101:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.101 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::102:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.102 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::103:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.103 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::104:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.104 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::105:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.105 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::106:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.106 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::107:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.107 Token: Invalid
Destination: 2A03:6B9:FC00:1F80:: Prefix length: 64
Nexthop : FE80::108:1:C2 Flags: UG
Time stamp : 0xb5e3 Label: Null
Interface : HGE1/0/25.108 Token: Invalid
Server can ping
ping6 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1
PING 2A03:6B9:FC00:1F80:6B9:FC00:1F80:1(2a03:6b9:fc00:1f80:6b9:fc00:1f80:1) 56 data bytes
64 bytes from 2a03:6b9:fc00:1f80:6b9:fc00:1f80:1: icmp_seq=1 ttl=61 time=0.057 ms
64 bytes from 2a03:6b9:fc00:1f80:6b9:fc00:1f80:1: icmp_seq=2 ttl=61 time=0.049 ms
64 bytes from 2a03:6b9:fc00:1f80:6b9:fc00:1f80:1: icmp_seq=3 ttl=61 time=0.039 ms
64 bytes from 2a03:6b9:fc00:1f80:6b9:fc00:1f80:1: icmp_seq=4 ttl=61 time=0.035 ms
We suspect that the device's routing resources are insufficient. We checked the device's IPv6 mode, and the result is as we expected.
<lab-kr-6s98>display hardware-resource routing-mode
Routing-mode resource(routing-mode), all supported modes:
ipv6-64 ipv6-64 supported
ipv6-128 ipv6-128 supported
-----------------------------------------------
Default Current Next
ipv6-64 ipv6-64 ipv6-64
Customer is using ipv6-64 mode，so the routing resouce for ipv6 128 mask is not enough
|
Mode |
MAC address table |
ARP/ND table |
Routing tables (IPv6-64) |
Routing tables (IPv6-128) |
|||||
|
IPv4 |
IPv6 |
IPv4 |
IPv6 |
||||||
|
0-64 |
128 |
0-64 |
65-127 |
128 |
|||||
|
NORMAL |
96K |
80K/40K |
162K |
80K |
40K |
160K |
65K |
65K |
73K |
|
MAC |
288K |
16K/8K |
32K |
16K |
8K |
32K |
8K |
4K |
8K |
|
ROUTING |
32K |
16K/8K |
324K |
165K |
8K |
324K |
73K |
73K |
73K |
|
ARP |
32K |
272K/136K |
32K |
16K |
136K |
32K |
8K |
4K |
143K |
|
DUAL-STACK |
32K |
16K/8K |
324K |
165K |
8K |
87K |
86K |
86K |
86K |
|
EM |
32K |
16K/8K |
32K |
16K |
8K |
32K |
8K |
4K |
8K |
Solution
If you want to use ipv6-128 mask route，you need to change the routing-mode to ipv6-128.
Here is the command：
hardware-resource routing-mode ipv6-128