pondělí 17. března 2014

How to Configure Cisco 2960 S to Route?

Našel jsem velmi zajimavý článek týkající se Cisco 2960S a routrování.
Musím si ho sem přidat, protože příště už ho docela určitě nenajdu.
Originální článek je na této adrese: http://www.cisco1900router.com/how-to-configure-cisco-2960-s-to-route.html
It’s known that Cisco 2960 series are layer 2 switches, but now, we will configure Cisco 2960 s to route so that it has the functions of layer 3 switches. Generally speaking, the Switch Database Management template (SDM) needs to be changed to “Lanbase-routing”. A reboot is (always) needed after changing the SDM template. After reboot, it’s just like enabling routing on any other Layer 3 switch with the command “ip routing” from global config.
Cisco 2960 with function of layer 2 switch

First we’ll change the SDM template:
SwitchA(config)#sdm prefer lanbase-routing
Changes 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.
System configuration has been modified. Save? [yes/no]: y
Proceed with reload? [confirm]
After changing the SDM template, we are reminded that we’ll need to reboot and also given a command to verify the change after the next boot.
Let’s verify:
SwitchA#show sdm prefer
The current template is “lanbase-routing” template.
 The selected template optimizes the resources in the switch to support this level of features for 8 routed interfaces and 255 VLANs.
  number of unicast mac addresses:  4K
  number of IPv4 IGMP groups + multicast routes:   0.25K
  number of IPv4 unicast routes:  4.25K
  number of directly-connected IPv4 hosts: 4K
  number of indirect IPv4 routes: 0.25K
  number of IPv4 policy based routing aces: 0
  number of IPv4/MAC qos aces: 0.125k
  number of IPv4/MAC security aces: 0.375k
The change was successful and we’re given the details about this SDM template.
Now seems like a good time to touch on the limitations of the layer 3 capabilities on 2960 s. As we see in the output above, we’re limited to 8 routed interfaces. These will be SVIs. At this point, the 2960s don’t support routed physical interfaces (“no switchport”). Another important note is that we’re only allowed 16 static routes and there is no dynamic routing capability.
Now we’ll enable IP routing and configure a couple SVIs:
SwitchA#conf t
SwitchA(config)#ip routing
SwitchA(config)#int vlan 15
SwitchA(config-if)#ip add
SwitchA(config-if)#int vlan 25
SwitchA(config-if)#ip add
SwitchA#sh ip route
C is directly connected, Vlan15
C is directly connected, Vlan25
Even now, I’m still amazed that we can do this with a 2960. As expected, it’s working. We have two SVIs and we can see the routing table reflect this. There are many scenarios where “layer 3 2960s” could be useful.
The material is originally referred from: 2960s-can-route
More tips on Cisco 2960 switches at:

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