Subject: [Errata Held for Document Update] RFC7938 (5477)

From: RFC Errata System <[email-masked]>
Date: Sat, 3 Nov 2018 19:43:39 -0700 (PDT)

The following errata report has been held for document update 
for RFC7938, "Use of BGP for Routing in Large-Scale Data Centers". 

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You may review the report below and at:
http://www.rfc-editor.org/errata/eid5477

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Status: Held for Document Update
Type: Editorial

Reported by: Klemens Schragel <[email-masked]>
Date Reported: 2018-08-24
Held by: Martin Vigoureux (IESG)

Section: 3.2.3

Original Text
-------------
   The small example of topology in Figure 3 is built from devices with
   a port count of 4.  In this document, one set of directly connected
   Tier 2 and Tier 3 devices along with their attached servers will be
   referred to as a "cluster".  For example, DEV A, B, C, D, and the
   servers that connect to DEV A and B, on Figure 3 form a cluster.  The
   concept of a cluster may also be a useful concept as a single
   deployment or maintenance unit that can be operated on at a different
   frequency than the entire topology.

Corrected Text
--------------
   The small example of topology in Figure 3 is built from devices with
   a port count of 4. By introducing an additional Tier the 4-port
   Tier 1 device has still two unused ports to connect further devices,
   therefore scaling from a maximum of 8 servers in a 3-stage Clos to a
   maximum of 16 servers in this 5-stage Clos.
   In this document, one set of directly connected Tier 2 and Tier 3
   devices along with their attached servers will be referred to as a
   "cluster".  For example, DEV A, B, C, D, and the servers that
   connect to DEV A and B, on Figure 3 form a cluster.  The concept of
   a cluster may also be a useful concept as a single deployment or
   maintenance unit that can be operated on at a different frequency
   than the entire topology.

Notes
-----
Section does not properly describe where the scaling happens, also the depicted topology still connects only 8 servers (the same amount as with a 3-stage Clos). The reader can grasp the scaling only when looking very carefully at the figure.

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RFC7938 (draft-ietf-rtgwg-bgp-routing-large-dc-11)
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Title               : Use of BGP for Routing in Large-Scale Data Centers
Publication Date    : August 2016
Author(s)           : P. Lapukhov, A. Premji, J. Mitchell, Ed.
Category            : INFORMATIONAL
Source              : Routing Area Working Group
Area                : Routing
Stream              : IETF
Verifying Party     : IESG