I'll take a stab since I just finished reading that in the CCNP switching manual and it'll be a good test :)
It depends on the setup eg, whether or not there's to be multiple vlans and, if so, whether or not the two vlans are to communicate etc. On the router you need to configure a subinterface on the physical ethernet port for each of the vlans and for that subint connection to trunk then specify the encapsulation there (either isl or dot1q) and the vlan number that will be assigned on the switch. Then configure the port on the switch that the router is connected to for the same trunking protocol. Then configure the vlan domain, and the vtp mode (server, client or transparent) on the switch. Then configure the vlans. eg... on the router.... interface FastEthernet2/0 no ip address ip helper-address x.x.x.x speed 100 full-duplex end interface FastEthernet2/0.1 encapsulation dot1q 5 ip address 192.168.5.1 255.255.255.0 ip helper-address x.x.x.x no ip redirects end Note the encapsulation dot1q 5. 5 is the number of the vlan as will be configured on the switch. In this case it's also the number of the subnet (a tip from Mr. Letterman). Dont use vlan number 1 or 1-1005. Im shaky on the command syntax and I don't have an IOS switch (i just ordered my 3550's last week) but on a CLI switch it would be.... set vtp domain mydomain (sets vtp domain name to mydomain) set vtp mode server (sets the switch in server mode - will transmit vlan info out all trunk ports to client mode machines) set trunk 1/1 nonegotiate dot1q 1-1005 (set the trunking protocol to dot1q for all vlans. Note: vlan 1 should be reserved for administration, 1001 is reserved by Cisco and 1002-1005 are reserved for tokenring bridging) set vlan 5 name subnet5 (define vlan number 5 with name of subnet 5) set vlan 5 2/1 (put port 2/1 on vlan 5. 802.1q (dot1q) is recommended as it only adds 4 bytes to the frame after the destination address in the IP header (2 bytes are the trunking protocol id, 3 bits for priority, 1 bit for CFI (whether or not the mac address is listed in canonical format), 12 bits for the vlan id). ISL encapsulates the frame with a 24 byte header and a 4 byte crc. Way more overhead... Any input on the IOS commands would be appreciated and Im still foggy on the trunking negotiation! Is it that one side is hard set to the protocol and the other is set noneogtiate so that it won't try and change it? (Any other input would be appreciated as well. Especially if I missed something obvious!) -----Original Message----- From: simon watson [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 01, 2003 1:02 AM To: [EMAIL PROTECTED] Subject: VLAN Tagging on Cat 3550 [7:71703] Hi Guys A client wants a Cat 3550 configured for VLAN tagging, I have not done one of these before so how do I configure the switch, also there is a Cisco 2600 router also connected to the switch.Do I need to configure the router to accomodate VLAN tagging (and any router that packets of the VLAN goes through ?) Thanks Simon. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71717&t=71703 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
