How to enable IPv6 support on a Cisco catalyst 3560 Switch
Yes it is an old Switch, but for a lab environment, we can use it. 🙂
In this article, we’ll see how to upgrade the Cisco Catalyst3560 Switch to support IPv6. A small picture just for you!!
If you have tried to configure IPv6 on this Switch model (a layer 3 switch), you may have noticed that the IPv6 commands are not working. Let’s see this in action:
| 3560(config)#ipv6 ? % Unrecognized command |
 If you look at the description of this switch, you’ll see that it supports the IPv6 protocol. So where are these commands hiding?
In fact the 3560 Switch has a feature called Switch Database Management (SDM). SDM helps the switch to manage the resource allocation of every feature. This means that there are some features that are disabled in the default template. So, if we want to work with these features, we need to enable them.
Let’s take a look at the default template:
| 3560#show sdm prefer The current template is “desktop default” template. The selected template optimizes the resources in the switch to support this level of features for 8 routed interfaces and 1024 VLANs. number of unicast mac addresses:Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 6K number of IPv4 IGMP groups + multicast routes:Â Â 1K number of IPv4 unicast routes:Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 8K number of directly-connected IPv4 hosts:Â Â Â Â Â Â 6K number of indirect IPv4 routes:Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2K number of IPv4 policy based routing aces:Â Â Â Â Â Â Â Â 0 number of IPv4/MAC qos aces:Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 0.75K number of IPv4/MAC security aces:Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 1K |
 You can see that default template supports 8 routed interfaces and 1024 VLANs. So there is no IPv6 feature enabled. So let’s enable it:
| 3560 (config)#sdm prefer ? access            Access bias default            Default bias dual-ipv4-and-ipv6 Support both IPv4 and IPv6 routing            Unicast bias vlan              VLAN bias |
You can see that there are a lot of templates, and dual-Ipv4-and-IPv6 is the template that we’re interested in. So we’ll choose this template:
| 3560 (config)#sdm prefer dual-ipv4-and-ipv6 ? default  Default bias routing  Unicast bias vlan    VLAN bias |
Here, you can see that there are a lot of options for this template; this means that we can give more resources to IPv4 and IPv6 routing, or more resources to VLAN. For us, we will choose the default options.
| 3560 (config)#sdm prefer dual-ipv4-and-ipv6 DefaultChanges to the running SDM preferences have been stored, but cannot take effect until the next reload. Use ‘show sdm prefer’ to see what SDM preference is currently active. |
 I think that the message is clear! The SDM preferences will take effect after the reload of the Switch.
Let’s see it his is true!
| 3560#show sdm prefer The current template is “desktop IPv4 and IPv6 default” template.The selected template optimizes the resources in the switch to support this level of features for 8 routed interfaces and 1024 VLANs.number of unicast mac addresses:                2K number of IPv4 IGMP groups + multicast routes:  1K number of IPv4 unicast routes:                  3K number of directly-connected IPv4 hosts:      2K number of indirect IPv4 routes:                1K  number of IPv6 multicast groups:               1.125k  number of directly-connected IPv6 addresses:    2K  number of indirect IPv6 unicast routes:          1K number of IPv4 policy based routing aces:        0 number of IPv4/MAC qos aces:                    0.5K number of IPv4/MAC security aces:                1K number of IPv6 policy based routing aces:        0  number of IPv6 qos aces:                        0.625k  number of IPv6 security aces:                    0.5K |
 You can see that IPv6 feature is enabled on the Switch. And now, we can enable the Ipv6 unicast-routing globally.
| 3560(config)#ipv6 unicast-routing |
 Note that I used the 3560 IOS version 12.2.55-SE9.
I hope this was helpful for you, and if it was, just leave a comment.
Thanks for the step-by-step guide
Thank you.