07-22-2007 07:04 AM - edited 03-05-2019 05:25 PM
I am replacing a failing 4500 switche with a newer 4500. This should have been easy but the old switch is using CATOS and the new one has IOS installed. I am slowly recreating the config but have come across something I am not sure about. I have the following line set port channel 2/1-4 183 in the old config. As far as I can see this is aggregating interfaces 2/1-4 is this correct? What does the 183 mean is it just an identifier?
In the router part of the config I have interface Port-channel1.2 and this has an IP address and 802.1q set if I do SH VLAN I can see that this is vlan 2. Can I just use interface vlan 2 and assign it an IP address in IOS?
07-22-2007 08:14 AM
Hi Tim
Set port channel 2/1-4 183 is indeed aggregating ports 2/1-4 into an etherchannel. The 183 is the admin group which is an identifier between 1 and 1024 and is an optional value.
With IOS you would just create a vlan 2 interface and assign it the IP address as you say. Obviuosly make sure the vlan exists at layer 2.
HTH
Jon
07-23-2007 12:00 AM
IOS equivalent of those commands are (assuming the port is trunk):
interface range Fa (or Gi) 2/1 - 4
switchport
channel-group 1 mode on
no shutdown
interface po 1
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan XXX,YYY,ZZZ...
switchport mode trunk
Fa or Gi depending on interface type. You can ignore "183", as per Marshall
07-23-2007 12:14 AM
Hi Pavlo
I'm not sure the above config will achieve the same thing. Tim said that the port-channel was po1.2 and had an IP address assigned to it. If that's the case it is acting as a Layer 3 interface so he will need to create a layer 3 SVI on the new 4500.
The config you supplied will only create a layer 2 etherchannel.
Regards
Jon
07-23-2007 01:31 AM
Jon,
The config pasted by the original poster was indeed for layer 2 ether-channel only. Cat4006 was layer 2 switch only with Sup2 running CatOS.As mentioned there was router card on the chassis which was 4232-L3 and was used for inter-vlan routing across the switch. I think the port-channel interface that the original poster was referring was only for inter-vlan routing across the switch backplane. It was a requirement for creating a port-channel on the internal gigabit ports between the sup and the routercard across backplane for interlvlan routing.
Please see the link below:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4000/inst_nts/78_10164.htm#230108
-amit singh
07-23-2007 01:48 AM
Hi Amit
Okay now i am confused. I have used the 4006 switch in this mode before and an aware of having to create a port-channel interface for inter-vlan routing.
But isn't that the whole point. If there is a po1.2 with an ip address this means that there must be inter-vlan routing happening on the old 4006. So to replicate that onto the new 4500 with IOS you have to create a layer 3 SVI ??
Jon
07-23-2007 02:28 AM
Jon,
Agree, with you on this. Yes, for inter-vlan routing, layer3-SVI's need to be created.
-amit singh
07-23-2007 07:20 AM
Thanks for the replies. I have created VLAN interfaces and the routing table is popuplated so I think that side is working OK. I need to start tracing fibre cables to work out what interfaces I need to confiure etherchannel on.
One thing I have noticed is that when I plug my laptop into the switch I get a DHCP address assigned by it with an IP address in the same range as the first VLAN. As far as I can see there is nothing in the config that mentions DHCP is this normal.
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