RFC Errata


Errata Search

 
Source of RFC  
Summary Table Full Records

Found 3 records.

Status: Verified (3)

RFC 6621, "Simplified Multicast Forwarding", May 2012

Source of RFC: manet (rtg)

Errata ID: 3499

Status: Verified
Type: Technical

Reported By: Errol Lloyd
Date Reported: 2013-02-26
Verifier Name: Adrian Farrel
Date Verified: 2013-02-28

Section B.4. says:

  1.  Initialize the set "MPR" to empty.

   2.  Initialize the set "N1" to include all 1-hop neighbors of "n0".

   3.  Initialize the set "N2" to include all 2-hop neighbors, excluding
       "n0" and any routers in "N1".  Nodes that are only reachable via
       "N1" routers with router priority values of NEVER are also
       excluded.

   4.  For each interface "y" in "N1", initialize a set "N2(y)" to
       include any interfaces in "N2" that are 1-hop neighbors of "y".

   5.  For each interface "x" in "N1" with a router priority value of
       "ALWAYS" (or using the CF relay algorithm), select "x" as an MPR:

       A.  Add "x" to the set "MPR" and remove "x" from "N1".

       B.  For each interface "z" in "N2(x)", remove "z" from "N2".

       C.  For each interface "y" in "N1", remove any interfaces in
           "N2(x)" from "N2(y)".

   6.  For each interface "z" in "N2", initialize the set "N1(z)" to
       include any interfaces in "N1" that are 1-hop neighbors of "z".

   7.  For each interface "x" in "N2" where "N1(x)" has only one member,
       select "x" as an MPR:

       A.  Add "x" to the set "MPR" and remove "x" from "N1".

       B.  For each interface "z" in "N2(x)", remove "z" from "N2" and
           delete "N1(z)".

       C.  For each interface "y" in "N1", remove any interfaces in
           "N2(x)" from "N2(y)".

   8.  While "N2" is not empty, select the interface "x" in "N1" with
       the largest router priority that has the number of members in
       "N_2(x)" as an MPR:

       A.  Add "x" to the set "MPR" and remove "x" from "N1".

       B.  For each interface "z" in "N2(x)", remove "z" from "N2".

       C.  For each interface "y" in "N1", remove any interfaces in
           "N2(x)" from "N2(y)".




It should say:

  1.  Initialize the set "MPR" to empty.

   2.  Initialize the set "N1" to include all 1-hop neighbors of "n0".

   3.  Initialize the set "N2" to include all 2-hop neighbors, excluding
       "n0" and any routers in "N1".  Nodes that are only reachable via
       "N1" routers with router priority values of NEVER are also
       excluded.

   4.  For each interface "y" in "N1", initialize a set "N2(y)" to
       include any interfaces in "N2" that are 1-hop neighbors of "y".

   5.  For each interface "x" in "N1" with a router priority value of
       "ALWAYS" (or using the CF relay algorithm), select "x" as an MPR:

       A.  Add "x" to the set "MPR" and remove "x" from "N1".

       B.  For each interface "z" in "N2(x)", remove "z" from "N2".

       C.  For each interface "y" in "N1", remove any interfaces in
           "N2(x)" from "N2(y)".

   6.  For each interface "z" in "N2", initialize the set "N1(z)" to
       include any interfaces in "N1" that are 1-hop neighbors of "z".

   7.  For each interface "w" in "N2" where "N1(w)" has only one member, "x",
       select "x" as an MPR:

       A.  Add "x" to the set "MPR" and remove "x" from "N1".

       B.  For each interface "z" in "N2(x)", remove "z" from "N2".

       C.  For each interface "y" in "N1", remove any interfaces in
           "N2(x)" from "N2(y)".

   8.  While "N2" is not empty, select the interface "x" in "N1" with
       the highest router priority [break ties in favor of the node with the 
       largest number of members in "N_2(x)"] as an MPR:

       A.  Add "x" to the set "MPR" and remove "x" from "N1".

       B.  For each interface "z" in "N2(x)", remove "z" from "N2".

       C.  For each interface "y" in "N1", remove any interfaces in
           "N2(x)" from "N2(y)".




Notes:

There are three changes:

On line 7, the first and second occurrences of x are replaced by w, and then x is given as the name of the sole member of N1(w).

On line 7B, the phrase 'delete "N1(z)" is dropped to be consistent with the rest of the algorithm.

On line 8 some rewording is done for clarification.

This errata prepared in consultation with Justin Dean and Gus Macker.

Errata ID: 3640

Status: Verified
Type: Technical

Reported By: Joseph Macker
Date Reported: 2013-06-06
Verifier Name: Adrian Farrel
Date Verified: 2013-06-06

Section A.4 says:

  4.  If "RtrPri(n0)" is greater than that of all tuples in the union
      of "N1" and "N2", then "n0" selects itself as a relay, and no
      further steps are taken.

It should say:

  4.  If "RtrPri(n0)" is greater than that of all tuples in
      "N1", then "n0" selects itself as a relay, and no
      further steps are taken.

Notes:

The initial verbal description of the E-CDS algorithm in first paragraph A.1 pg 40 is correct..as follows

1. If an SMF router has a higher ordinal (Router Priority, Router
ID) than all of its symmetric neighbors, it elects itself to act
as a forwarder for all received multicast packets.

But LATER in A.4 pseudocode Step 4 contains a bug. N2 (2 hop neighbors are included in this step). This pseudocode bug can cause incorrect behavior to occur.

Errata ID: 4098

Status: Verified
Type: Editorial

Reported By: Joe Macker
Date Reported: 2014-09-04
Verifier Name: Adrian Farrel
Date Verified: 2014-11-18

Section Appendix B says:

This distributed relay set selection technique has been shown to 
approximate a minimal connected dominating set (MCDS) in [JLMV02].

It should say:

This distributed relay set selection technique has been shown to 
approximate a minimum connected dominating set (MCDS) in [JLMV02].

Notes:

Minimum connected dominating set [1] is the established terminology and
minimal was an editorial error.

[1] Sampathkumar, E.; Walikar, HB (1979),
"The connected domination number of a graph", J. Math. Phys. Sci 13 (6): 607–613.

Report New Errata



Search RFCs
Advanced Search
×