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

Errata ID: 148
Status: Held for Document Update
Type: Editorial
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

The final paragraph on page 8,

   The following table illustrates typical memory requirements of a
   router running BGP.  We denote the average number of routes
   advertised by each peer as N, the total number of unique AS paths as
   A, 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 number of octets required to store a network
   as R, and the number of bytes required to store one AS in an AS path
|  as P.  It is assumed that each network is encoded as four bytes, each
   AS is encoded as two bytes, and each networks is reachable via some
|  fraction of all the peers (# BGP peers/per net).  For purposes of the
|  estimates here, we will calculate MR = (((N * R) + (M * A) * P) * S).
                                                             ^^^^ ^^^^

and the table on page 9,
                                       vvvvvvvvvvvvvvvvvvv
|  # Networks  Mean AS Distance # ASes # BGP peers/per net   Memory Req
|      (N)             (M)        (A)          (P)              (MR)
   ----------  ---------------- ------ ------------------- -------------
     100,000           20         3,000         20           10,400,000
     100,000           20        15,000         20           20,000,000
     120,000           10        15,000        100           78,000,000
     140,000           15        20,000        100          116,000,000

exhibit additional issues:

- The text defines 'P' as
    "the number of bytes required to store one AS in an AS path"
  while apparently in the table (P) means
    "# BGP peers/per net".

- 'S' in the formula in the last line of page 9 is not defined
  anywhere in the text.

- "# BGP peers/per net" IMHO does not even make sense in the
  context of BGP, since BGP speakers represent ASes, not networks
  (prefixes).

I do not have a proposal for an easy way to get rid of these
inconsistencies.
Please check.

Notes:

There is clearly a problem with the text, but it does not impact interoperability and should be looked at when the RFC is revised.

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