/127 between routers?

[Ryan Harden]

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On 01/05/2010 10:59 AM, Michael K. Smith - Adhost wrote:
> 
> We use /64's for interfaces/interface sets/ and route /48's through and
> to those interfaces.  Am I in the minority when I look at the fact that
> I have 65k /48's and don't really feel the need to subnet beyond a /64?
> Operationally, it makes things much simpler as well (in my opinion, of
> course).  I get my lower level techs to think in terms of /64's and
> /48's rather than those plus any number of more specific subnets.  I
> haven't had to do much to tweak our backend systems (all home grown) to
> manage these values, etc.
> 

Those of us with a single /48 only have 65k /64s. We're using /126's on
backbone ptp links. Not so much for address conservation but for ease of
management.

1) ACLs are much easier to write. Blocking incoming connections to ptp
links at the border becomes a single /64 ACL, etc.

2) Yes ::1 and ::2 would be pretty easy to remember if we used /64s
everywhere, but we're network engineers. It's just as easy to learn
::1/::2, ::5/::6, ::9/::a, etc.

We're still debating whether or not to use /126 or /64 on
building-backbone links. Right now the compromise is 'use /126 where we
control both sides, /64 where far router is customer/department owned.'

/Ryan

- -- 
Ryan M. Harden, BS, KC9IHX		Office: 217-265-5192
CITES - Network Engineering		Cell:  	217-689-1363
2130 Digital Computer Lab		Fax:    217-244-7089
1304 W. Springfield	 		email:  hardenrm at illinois.edu
Urbana, IL  61801 			

      University of Illinois at Urbana/Champaign - AS38
	   University of Illinois - ICCN - AS40387
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