CCNA, CCDA, CCNP, CCDP, CCIP, CCVP and CCIE
Hello, I have two questions regarding Cisco 2950 Switch..... (1) Why can not we set an IP address on Cisco 2950 switch's ports? and why does it show "no ip address" underneth each port when we issue "show runn" command when we can not set an IP? (2) Why first vlan goes down while we make second vlan, give it an ip address different from the previous one and issue a "no shutdown" command?
The 2950 switch is purely a layer-2 switch, and it does not contain any layer-3 routing functions. This is why it only allows you one IP address in the box, which is the address you use for management. In addition, it allows you to specify which VLAN this address is on, but it only allows you one at a time.As for why the interfaces show no ip address on a show run ... I don't really know. Perhaps they did it for consistency with the other IOS devices that do contain layer-3 functions.Kevin DorrellLuxembourg
The 3550 can perform L2 and L3 functions. It's quite a piece of hardware.For the CCNA exam - as I tell my students, it's great to know about the 3550 and that there are L2/L3 devices out there, but for the purposes of the exam, a switch is a switch and a router is a router.Chris BryantCCIE #12933www.thebryantadvantage.comFree CCNA and CCNP tutorials!
There are quite a few switches now that do layer-3 as well as layer-2. It is mainly the low end switches - the 2950 series - that do layer-2 only. It is logical that more and more switches should do layer-3, because most modern LANs are VLAN based, and you need layer-3 to enable communication between the VLANs.The most quoted multilayer switch is the 3550. This is the standard workhorse, and is the one that appears in the CCIE labs, probably the CCNP as well, and many other places. Having said that, I must confess ... I have never actually used one. What I have used is a Catalyst 4500 series, with the more recent supervisor cards - these are all capable of layer-3 functions.So the short answer is that it is: only the low end switches that are restricted to layer-2; the high end switches are multilayer.Hope this helps.Kevin DorrellLuxembourg