Trunking is a way to carry traffic from several VLANs over a point-to-point link between the two devices. Two ways in which Ethernet trunking can be implemented are: 1) ISL - InterSwitch Link (Cisco proprietary protocol, and not supported by the 2940 or 2950 series switches) 2) 802.1Q (Institute of Electrical and Electronics Engineers (IEEE) standard) For Catalyst 2900XL/3500XL/2940/2950/2970 Switches: Catalyst 2940 and 2950 series switches only support 802.1q trunking, and do not support ISL trunking. On a 4 MB DRAM Catalyst 2900XL switch, trunking is only supported with the following trunking-capable modules: WS-X2914-XL-V: 4-port 10/100 ISL/802.1Q switch module WS-X2922-XL-V: 2-port 100BaseFX ISL/802.1Q switch module WS-X2924-XL-V: 4-port 100BaseFX ISL/802.1Q switch module WS-X2931-XL: 1000BaseX uplink for Catalyst 2900 XL WS-X2932-XL: 1000BaseT uplink for Catalyst 2900 XL To get the compactability chart please refer; http://www.cisco.com/en/US/tech/tk389/tk815/technologies_configu
Technology Director