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3com 4400 vlans

Hi,
I am trying to configure 3com 4400 switch with multiple vlans, I setup two vlans 3 and 4 assigned port 3 on the switch to vlan 3 and port port 4 to vlan 4 I want to let port 5 on the same switch to be part of the two vlans, I changed the type of the port 5 to hybrid, and added the port as a tagged port to vlan 3 and 4 but cannot communicate with the two pc's on vlans 3 and 4.
what is the problem
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saimirka
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saimirka
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1 Solution
 
jfradyCommented:
First off I think you're talking about a switch 4500.  The 4400 doesn't use the hybrid terminology.

Unless the two PC's have the capability of applying VLAN tags to their traffic this will not work.  That is if I'm understanding you correctly.  I'll make some assumptions and give answers based on those assumptions.

If you are trying to route between two VLAN's you need to have a router somewhere that is in both VLAN's and has a route between the two networks.  If indeed you have a 4500 switch it is a Layer 3 (router) switch.  In order for the 2 VLAN's to talk they would have to have Layer 3 addresses set up.  Each VLAN would have an IP interface assigned to it, the network devices on each vlan would be configured to point to the switch address, and then it would work.  

If you have a 4500 switch:  a hybrid port is used when you have one untagged VLAN and one or more tagged VLAN's on a single port.  In your description this doesn't sound the case.  If you want to connect two switches together and have multiple VLAN's traverse it you would use a Trunk port.

In your question it isn't clear exactly what you are trying to do.  Hopefully this helps.  If you add further clarification we could likely help more.
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saimirkaAuthor Commented:
Sorry my switch is 4200g 48 ports, I am trying to have a computer to be a member of two vlans (3 and 4 ) and communicate with the two stations without the two stations can communicate with each other. I don't want to use routing between the two vlans.
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jfradyCommented:
Unless your computer can participate in tagged VLAN's you cannot do this.  If the computer (and NIC) can do tagged VLAN's you need to configure both VLAN's on the machine and plug it into a port on the switch that you setup as a Trunk port with membership in both VLAN's.

If you computer and NIC cannot do tagged VLAN's you will have to enable routing if you want this to work.

I don't know why you're trying to do what you are doing.  If you're doing it for security then this wouldn't work but if the goal is just to have the one machine be able to communicate with two others, but the two others not communicate with each other, you could add an additional IP address to the computer and not use VLAN's.
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saimirkaAuthor Commented:
I am trying to solve a problem I have, I need to implement IPTV on my network but in order not to flood the network with unnecessary multicast packets, I need to create a vlan for that iptv device and restrict membership to it, example I might need to add two ports from the first switch and other port from another switch with different vlans to this vlan but restrict others, and still preserve old vlans membership. I don't think in large networks when implementing vlans they don't have a situation when computer needs to be a member of more than vlanm lets take domain contollers all the pc's in an network need to communicate with the dc, so the dc must be a member of all the vlans.
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jfradyCommented:
In your example the DC would be on a different subnet if it was on a separate VLAN.  All the traffic would be routed from workstations on various subnets to the DC.  

For multicast containment there are other methods that can operate at either layer 2 or layer 3.  IGMP, IGMP Snooping, GARP, DVMRP, MOSPF etc.

It is true that a layer 2 swiitch that cannot do multicast will flood all packets to all ports.  This is simple to overcome by using features that were built specifically for this like IGMP Snooping.  The thing is though that you have to have a layer 3 device to handle the multicast registrations such that your layer 2 switch can "snoop" them.

Do the devices that need to be on the IPTV network also need to be in the other (assumably data) VLAN?  If not you can simply do port based VLAN's for the IPTV devices and trunk links between the switches.  Keep in mind though that on the trunk link between switches the multicast traffic will share the bandwidth with the other VLAN.
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saimirkaAuthor Commented:
You are right about multicast, I have 3com 5500EI which could handle multicast registrations, but the problem is that I have another networks seperated by those 5500 switches which needs also to benefit from the iptv, Does multicasting to those networks creates any type of slowness on the network, or lets speak straight our network has about 500 to 600 pc's, does implemeting iptv affects the performance of the network (not all the users will have iptv on their desktops (about 100 or less will have iptv), Does implementing multicast and igmp solves the problem of flooding network ports for users not opening iptv or participating on sessions, because when I monitored the 3com switche after testing iptv on one switch I realized that all the active ports conserves about 54 mb even not participating on iptv.
Sorry for bad english
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jfradyCommented:
Yes.  Correctly configuring Multicast on the switches would alleviate the issue of multicast by pruning ports that do not subscribe.  The only concern would be if you backbone links between switches are already highly utilized and can't handle the additional burden of the multicast traffic.  You have some great hardware with the features built in to handle proper multicast containment and routing.  I would recommend using the 5500 as your IGMP querier and router.  Then all other layer 2 switches that connect in use IGMP snooping to limit multicast.
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