IPV6 Problem on Cisco 3550

[mrmozaffari]

Hey Guys,

I have problem with IPV6 connectivity, i have two Cisco 3550 switch and they are connected over a trunk link. The ios is

c3550-ipservicesk9-mz.122-44.SE6 , I have configured vlans on both switches and i numbered one vlan to vlan 91 ,they can ping each other when i configure ipv4 on both vlans so trunk link is functional, but when i m using IPV6 they can't ping each other!! they can only ping their own ip address not each other.

Switch1:

interface Vlan91

ip address 192.168.11.1 255.255.255.0

ipv6 address 2001:22::1/64

ipv6 enable

Switch2:

interface Vlan91

ip address 192.168.11.2 255.255.255.0

ipv6 address 2001:22::2/64

ipv6 enable

Please advise.

Regards,

Bahman.

[Gregory Snipes]

Have you enabled "IPv6 unicast-routing" under global config?

[mrmozaffari]

Yes, it's there

[Gregory Snipes]

Can you ping using link-local address?

[mrmozaffari]

I don't want to use link-local address.

[Julio Carvajal]

Hello,

Can you share the following command on both switches:

show ipv6 interface brief

[mrmozaffari]

I just made some changes to addresses.

Switch1:

Vlan91                     [up/up]

    FE80::20B:5FFF:FED9:1D00

    2001:22::2

    2001:22::5

Switch2:

Vlan91                     [up/up]

    FE80::208:7CFF:FE3A:3500

    2001:22::10

[Julio Carvajal]

Hello,

One question:

Can you enter the following command on both SVI interfaces:

 sdm prefer dual-ipv4-and-ipv6 default 

[mrmozaffari]

I don't have this command under SVI interface.

[Julio Carvajal]

Hello,

I do understand that you want to be able to ping the global unique address you are using in this setup but is there a way you could try to ping the other link-local address of the host?

How are you tying to ping?

Are you doing it like this:

ping ipv6 x:x:x:

Regards,

[mrmozaffari]

It's worse. I found  3550 only does ipv6 in software, only software.

The switch can send out IPv6 packets but cannot receive any, which means it drops inbound IPv6 packets sent to the

switch itself because the hardware seemingly cannot understand them.

[Julio Carvajal]

Hello,

I was about to post this :

IPv6  it is not supported in hardware unlike the 3560/3750 switches. There is no sdm template for ipv6 on the 3550

Doing some research I found the following information:

According to some tests, IPv6 is somewhat supported on the 3550 with

12.2(44)SE1 and SE2, however only in software. The switch can send out

IPv6 packets (that's why you are seeing EIGRP adjacency established

for a short time) but cannot receive any (that's why EIGRP adjacency

is flapping), which means it drops inbound IPv6 packets sent to the

switch itself because the hardware seemingly cannot understand them. I

also checked this behavior with Wireshark.

debug ipv6 packet

Mar 22 15:38:43: IPV6: source 2001:xxxx:xxxx:xxxx::2 (local)

Mar 22 15:38:43: dest FF02::1:FF00:2 (Vlan2)

Mar 22 15:38:43: traffic class 224, flow 0x0, len 72+8, prot 58,

hops 255, originating

Mar 22 15:38:43: IPv6: Sending on Vlan2

The interesting part is that IPv6 tunneling (GRE mode, because ipv6ip

mode cannot be selected) is working on the 3550 with the above IOS

versions. Enable ipv6 unicast-routing and create a tunnel interface,

assign an IPv6 address to it and set an IPv6 capable router's IPv4

address as the tunnel destination. It will work because the switch

will receive IPv4 packets and the IPv6 packets encapsulated into them

are processed by the CPU.

ipv6 unicast-routing

interface Tunnel6

no ip address

ipv6 address 2001:xxxx:xxxx:xxxx:6::2/112

ipv6 enable

tunnel source 192.168.1.5

tunnel destination 192.168.1.7

end

ipv6 route ::/0 2001:xxxx:xxxx:xxxx:6::1

c3550#ping 2001:xxxx:xxxx:xxxx::1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:xxxx:xxxx:xxxx::1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms

[Edwin Matos]

Correct as mention before software only. It will support RIP and OSPF but no EIGRRP.

[R1]======[R2]

Built a tunne ( Software )

and you should be able to ping and created ipv6 neigbors withou probblem