RFC 4274, "BGP-4 Protocol Analysis", January 2006

Errata ID: 3777
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Alfred Hoenes
Date Reported: 2006-07-08
Held for Document Update by: Stewart Bryant
Date Held: 2013-10-30

(5)  like (4)

Section 6.1.2, on page 8, exhibits similar symptoms as noted above.
The RFC says:

   To quantify the worst-case memory requirements for BGP, we denote the
   total number of networks in the Internet as N, the mean AS distance
   of the Internet as M (distance at the level of an autonomous system,
   expressed in terms of the number of autonomous systems), the total
   number of unique AS paths as A.  Then the worst-case memory
   requirements (MR) can be expressed as

           MR = O(N + (M * A))

   Because a mean AS distance M is a slow moving function of the
   interconnectivity ("meshiness") of the Internet, for all practical
   purposes the worst-case router memory requirements are on the order
|  of the total number of networks in the Internet multiplied by the
|  number of peers that the local system is peering with.  [...]

Apparently, the first part of that text has been revised eliminating
the role of the peering count.  Thus the last sentence should have
been updated accordingly, to make it match the new formula.

The second paragraph thus perhaps should say:

   Because a mean AS distance M is a slow moving function of the
   interconnectivity ("meshiness") of the Internet, for all practical
   purposes the worst-case router memory requirements are on the order
|  of the total number of networks in the Internet.  [...]

Notes:

from errata 148

Rather than follow this suggestion (and drop the number of peers term out of the prose) it may be more would be more accurate to insert a number of peers term into the formula, e.g. MR = O(P * (N + (M * A))), where P is the number of peers.

This does not impact interoperability and thus should be looked at in any future update of the RFC.

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