"surfer@mauigateway.com" <surfer@mauigateway.com> writes:
I am going to be cutting over about 75,000 DSL lines from one core network to another. Does anyone have recommendations on subnet and DHCP scope size? If I make them /23s I have to do about 145 subents. If I make them /22s I only have to do about 73. Being mainly an always on eyeball network I don't see any problems with making big subnets (/22).
I'd say aggregate as much as possible based on what your LNS/RAS equipment will handle in terms of actual customers. In my OSPF, I carry a /21 for each 7206VXR/NPE300 which may be a tad optimistic if current P2P trends continue as they have - time to work some NPE-G1s into my budget. Of course, on the other end of the scale I carry /32s for each static address customer, since that gives me maximum flexibility for LNS shuffling in the future (to distribute load). Peter Dambier is right that his ISP is avoiding .255 and .0. Older MS stacks (still plenty prevalent in the wild) get indigestion when handed those final octets, notwithstanding the fact that they aren't broadcast addresses on any network larger than a /24 or for one-ended use like PPP... if you don't exclude them you'll end up putting additional load on your help desk. The necessity to avoid .0 and .2555 results (on ciscos) in idioms such as this: ar01#sho run | inc ip local pool ip local pool ar01-dynamic 223.126.80.1 223.126.80.254 ip local pool ar01-dynamic 223.126.81.1 223.126.81.254 ip local pool ar01-dynamic 223.126.82.1 223.126.82.254 ip local pool ar01-dynamic 223.126.83.1 223.126.83.254 ip local pool ar01-dynamic 223.126.84.1 223.126.84.254 ip local pool ar01-dynamic 223.126.85.1 223.126.85.254 ip local pool ar01-dynamic 223.126.86.1 223.126.86.254 ip local pool ar01-dynamic 223.126.87.1 223.126.87.254 ar01#
<flameproof undies == on> suggestions, recommendations, advice?
scott
Uh... suggest/recommend/advise that you ought to use your full name in posts and not an alias and first name, as required in the NANOG Charter and AUP? http://www.nanog.org/aup.html item 7. Best, ---Rob (member of the list-admin team)