3com Vlan help

You don't specify if you are trunking anywhere but 3com tags the default vlan, Cisco does not. If you are using vlan 1 as the default vlan you will need to add the tagged command (native) to the all the Cisco trunk ports. In some of the 3coms it was possible to remove the tagging on vlan 1, there was an untagged option.

If your not trunking and simply using each fiber port defined in a vlan, do you have a route on the 5321 to the other vlans?

-Brian

Really thank you Brian for your reply , but it is my first time to get to vlans so there are some things i don't understand : 1- what is the benifit of trunking a port ? i read that there are three types of ports access, trunk and hybrid .....

2- what is tagging ???? that they are talking about alot in the documentation ... i think that i know about 802.1q but i don't understand what does it do ......

and about your question i ----> i have said before that i can ping any host in vlan1 from any host in vlan 3 or 2 or 4 or others ... but i can't ping the router which is a member of vlan 1 also...

thanks for help

Morning,

I don't remember seeing that everyone could ping everyone except the router in your post. It was early when I read it so I probably just missed that. That being said, it has to be simple routes missing in the router. The router needs to know where all the subnets are and how to get there. You need to add the routes pointing back to vlan 1's interface on the core switch for the other vlans subnets. Not knowing your topology and/or configs I can only asume that you have a L3 cabable core switch. To answer your other questions as simply as possible: 1, Access is used for end stations. Trunk carries multiple vlans. Hybrid basically means is auto-negotiates if it's a trunk or access port. 2, Tagging, not 802.1Q, that's an encapsulation type, basically tells the trunk what language to speak so it can read the tags. Tagging is the vlan header information, done on a router or switch, basically protects the packet from being read by the other vlans. When a packet comes in on say vlan 2, it's is tagged with a vlan 2 header which can only be read/removed by the switch or router. Vlans logically seperate networks, that "logic" is the tags. Lot more complicated than that and a lot more to it, but that's the jist.

-Brian

-Brian

When VLAN`s traffic passthrough the trunk link, the switch tag each frame send between switchs so that the receiving switch can know which vlan the frame belongs to.

In article , shen wrote: :When VLAN`s traffic passthrough the trunk link, the switch tag each :frame send between switchs so that the receiving switch can know which :vlan the frame belongs to.

802.1q requires that there be a single VLAN number (the "native" vlan) per port which will be sent without -any- 802.1q header, just as if it were a non-trunked port. This is an exception to the rule that "each frame" is tagged.

Good morning : Thank you all , now i added the routing table to the router and it works fine all vlans can access the router and vice versa ....... But still a problem, all ports are access and there isn't any trunk port. Brian ------> Do you advice to make the vlan ports trunk ports? and now i understood what is the difference between trunk and access. Brian ----!!!!!!!!!!! a small note before i go . They wrote in the documentation that trunk passes a tagged packet which can be discarded from almost all the network cards , but hybrid doesn't.