Re: [pim] What is the value of 'infinity'

["Christopher Thomas Brown" <ctbrown at nexthop.com>]

John Zwiebel wrote:
> 
> It may seem like a silly question, but I've found some interop
> problems for bidir DF-elections where some have selected 'infinity'
> to be 0x7fffffff and some have selected it to be 0xffffffff.
> 
> Given the info below, what is "infinity"?
> 
> The PIM RFCs (2117 and 2362) have the following statements -
> 
>   3.5.1 Sending Asserts
>      ...
>      If route is not found, use metric preference of 0x7fffffff
>      and metric 0xffffffff.
> 
> the new PIM sparse-mode spec says:
> 
>   assert_metric
>     infinite_assert_metric() {
>     return {1,infinity,infinity,0}
>   }

In PIM-SM the infinity value for metric preference is 31-bit so its
0x7fffffff. Since the BiDir specification makes reference to the PIM-SM
specification on comparison, I'd say that implies it should be a 31-bit
value.  If left to stand as is, I think this will continue cause confusion.
Perhaps, the BiDir authors should clarify this in the BiDir spec.

Chris

_______________________________________________
pim mailing list
pim at ietf.org
https://www1.ietf.org/mailman/listinfo/pim