At 11:43 AM 6/26/2003 -0500, Mark Smith wrote: >I never tried using sub's on the the LAN interface. I could have used VLAN's >at the time I initially set it up but didn't see a need for it at the time >(still don't unless it's the officiallly Cisco-blessed method and then I'd >just be curious as to why). I just set up a secondary and then later on I >got to wondering if I was "doin' the right thing". > >It ain't broke. Guess I don't need to fix it.
That's always a good guidance :), however I might have misunderstood the original question (I thought you were asking about subinterfaces without vlans). If you are interested in the advantage of using vlans over secondary IP addresses, then there are some. For example, vlans decrease the broadcast domain, ie. hosts on one VLAN won't drive hosts on other VLANs crazy by sending lots of broadcast packets. I also seem to remember that some routing protocols (OSPF or ISIS?) used to have some issues with secondary IP addresses. Unfortunately I don't recall the specifics. Thanks, Zsombor >Ask your router. I did, and it said: > >% Configuring IP routing on a LAN subinterface is only allowed if that >subinterface is already configured as part of an IEEE 802.10, IEEE 802.1Q, >or ISL vLAN. > >:) > >In other words, secondary IP addresses will do just fine. And btw you can >have more than one per interface (up to 255, or so?). > >You might also want to check out the other thread about encapsulations and >such. > >Thanks, > >Zsombor > >At 03:27 PM 6/26/2003 +0000, Mark Smith wrote: > >I have a router (actually a pair of them in HSRP but that's irrelavent) >that > >connects two networks in non-contiguous IP address ranges through a 100MB > >F/E TX port on the inside to an ISP network on the outside, also via a >100MB > >F/E TX port, at a colo facility. I have a half of a hundred MB pipe to the > >outside world. The two networks behind the router are independent of each > >other, seperated by PIX's behind the routers but, on occasion, they do > >communicate with each other. I currently have a primary and secondary IP > >address set on the inside F/E interface, one for each network. I've never > >seen any mention if sub-interfaces being used in Ethernet or Fast Ethernet > >interfaces in any Cisco literature. They primarily seem to be mentioned in > >regards to serial interfaces. Is there an advantage to using sub-if's here > >over a primary and secondary IP address? Any packet filtering is handled by > >the PIX's so I don't ever foresee the use of access-lists on the router. > >This router simply routes packets. I don't foresee the use of more than two > >networks inside but I suppose that's a slight possibility down the road if >I > >would need more IP addresses and couldn't get contiguous addresses. I'm >not > >sure if you can use more than a single secondary address on an interface or > >if you can pnly use a single one. I guess I'm not sure if "recommended > >practice" would be to always use sub-if's when connecting more than one > >network to any interface, use sub's only with serial i/f's and use > >primary/secondary addresses with F/E interfaces or if it's time to consider > >adding more F/E modules with 2 or more networks. I've used this > >primary/secondary config for a couple of years and it's worked fine but, as > >my colo facility is Sprint and they've decided to get out of the hosting > >biz, it would be a good time for me to reconfigure things during the move >if > >there is an advantage in doing so. > >Thanks. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71459&t=71459 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
