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multi mode port on catalyst 3560

Hi all,

Is the multi mode function available at the Catalyst 3560? Can i have one port operate on 2 or more different VLANs?? How is that done??

Regards
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merhi2405
Asked:
merhi2405
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2 Solutions
 
lrmooreCommented:
Yes, you just make that port a trunk port and trim the vlans that you don't want.
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3560/12225sed/scg/swvlan.htm#wp1100014

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ravisimpiCommented:
I think Tagged VLANs will solve your problem.  Every ethernet frame will have a VLAN ID added to it so you can put multiple VLANs over the same physical link/trunk. I am not sure wether Catalyst 3560 will support it or  not.


 Peace and Health
Ravi Simpi
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ravisimpiCommented:
Yes it supports.
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PennGwynCommented:
Note, by the way, that trunking is NOT what "multi-mode" refers to....

"Multi-mode" refers to low-level details of a fiber connection; typically a multimode fiber uses a larger diameter glass fiber and carries traffic for a shorter distance than the "single mode" alternative.  It tends to be cheaper, too.

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merhi2405Author Commented:
If I made a trunkport, I won't be able to connect it to a Pc with a NIC having two IPs each on a VLAN. a trunk port should be connected to another trunk port of a switch. Can I connect a trunk port to a PC/server ???
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ravisimpiCommented:
Well, i didnt consider that you just want to connect a PC to a port and should take part in different VLAN.
 If you are using trunk links between two switches then you will have to use 802.1Q Trunking Between them. Have a look at this link which clearly explains the procedure.

http://www.cisco.com/warp/public/473/88.html

 If you want to connect a PC to switch and want it to take part in more than one VLANs, then you will need a 802.1q awair NIC (network Interface card) or intelligent NIC, only then it is possible.
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ravisimpiCommented:
hey try the following thing on your switch
conf t
interface FastEthernet (port No)
 duplex full
 speed 100
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 2
 switchport mode trunk

 I think the last line tells the switch that the PORT is ready to take part in MULTIPLE VLANs

Just give it a try.
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ravisimpiCommented:
Uhmmmmm... That will make the switch understand that it is taking part in multiple VLANs. What about the PC which has NIC which wont understand the tagging.

  just configuring a port to Trunk wont solve the problem. You will have to have a 802.1q Aware NIC to be connected to that port.

 And I have heard somewhere that if you are using 'Linux kernel 2.2.14' it may be possible by patching its VLAN to support 802.1q.

  I don't have enough time now... May be tomorrow i will try to help you. Meanwhile let me know which operating system you are using.
  Peace and Health.
Ravi Simpi
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merhi2405Author Commented:
I am using windows server 2003
Thanks
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ravisimpiCommented:
Well... Uhmmmmm... Er......
The NIC driver for Windows must have the VLAN tagging functionality integrated into it. Can you check it with them?

I doubt they have integrated it.
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ravisimpiCommented:
I have seen some vendors who support VLAN trunking.

Example Intel Pro Series adapters come with a simple GUI for configuration of VLANs

http://www.lanarchitect.net/Articles/VLANTrunking/Implementation/index.htm

  Just check it out with your Vendor. If you are using Linux, it has this functionality native to the kernel. To enable VLAN tagging in linux, you need two things: the vlan rpm (e.g., vlan-1.8-23) and the 8021q kernel module. Once installed, the vconfig command can be used to create VLAN interfaces on an existing physical device.

Peace and Health
Ravi Simpi
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merhi2405Author Commented:
Hi,
Isnt it easier and more practical to have a port operating on two subnets??? I am sure that this is available in certain switches, but i m not sure if available on the 3650 catalyst.

Thanks
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ravisimpiCommented:
If a device has to take part in Different VLANS it should be able to add the 802.1Q tag ( look at http://www.cisco.com/en/US/tech/tk389/tk390/technologies_tech_note09186a0080094665.shtml  for more information )the outgoing frame and should be able to strip off the 802.1Q tag after reading the tag with the incomming frame.

  Now the port of your switch understand the 802.1Q for its incomming and out going frame. What about the NIC which is connected to that port? Will it understand the fragmentation of the frame sent by the switch?

  Well.. I don't know how well i have explained.. But i hope you understood what actually I mean to say.


Peace and Health.

 Ravi Simpi
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lrmooreCommented:
>more practical to have a port operating on two subnets???
Now you're talking a whole different perspective. Subnets are not always vlans unless you set them up that way.
A VLAN can certainly be in two subnets at the same time. Simply use "secondary" ip address on the vlan interface...
  interface vlan 2
   ip address 192.168.122.1 255.255.255.0
   ip address 192.168.123.1 255.255.255.0 secondary

Assign an interface to static access vlan2
Plug a PC into that interface and put 2 IP's on the NIC

Putting more than one IP on one NIC is not a really good idea, especially for a server. You get into dns/netbios problems where the networks sees the same netbios name with two different IP's bound to the same MAC address. You're setting yourself up for difficult troubleshooting.

The other answer is to use 802.1q capable NIC's.
The answers are all here, just not what you want to hear.

A third option on the 3560 is the concept of Private VLANs' where you can have some ports on their individual vlan and one port that can see them all. You still don't use different ip subnets or multiple IP's on the one server NIC.
 
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