Re: [bess] Last Call: <draft-ietf-bess-evpn-df-election-framework-06.txt> (Framework for EVPN Designated Forwarder Election Extensibility) to Proposed Standard

Anoop Ghanwani <> Fri, 07 December 2018 09:01 UTC

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From: Anoop Ghanwani <>
Date: Fri, 07 Dec 2018 01:00:50 -0800
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Subject: Re: [bess] Last Call: <draft-ietf-bess-evpn-df-election-framework-06.txt> (Framework for EVPN Designated Forwarder Election Extensibility) to Proposed Standard
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I have reviewed the doc and I have mostly editorial comments.




VLAN Bundle, VLAN bundle, VLAN-Bundle, VLAN-bundle -- make consistent
VLAN Aware Bundle, VLAN-aware bundle, VLAN-Aware Bundle -- make consistent
bridge table, Bridge Table -- make consistent (also add definition to
terminology section)
DF election, DF Election -- make consistent
Default DF Election, default DF Election -- make consistent
non-DF -> NDF

Section 1

double Q-in-Q tags -> Q-in-Q tags

double is redundant

Section 2.1

Fig 1 is a bit confusing.  If the idea of the rectangle is to show a
core, then why have connections between PE1 and PE2, PE3, but not
between PE1 and PE4?

Layer-2 devices are particularly susceptible to forwarding loops
because of the broadcast nature of the Ethernet traffic.
The effect of forwarding loops in a Layer-2 network is particularly
severe because of the broadcast nature of Ethernet traffic and the
lack of a TTL.

Section 2.2.1

a v4 or v6 peering -> an IPv4 or IPv6 peering

>From a forwarding perspective, this is
a churn, as it results in re-programming the PE ports as either
blocking or non-blocking at potentially all PEs when the DF changes.

Why would the reprogramming change at all PEs?  It should change for
at most 2 PEs for each (ES,EVI) being reprogrammed.  Maybe authors
were trying to convey something else?

Section 2.3

DF Election procedure Generally
Missing a period.

Section 3

specification in EVPN -> EVPN specification

Section 3.1

DF WAIT, DF_WAIT -- make consistent
DF Wait timer -- where is this defined?
Ethernet Segment Route -> Ethernet Segment route
stop DF timer ->  stop DF wait timer (?)
start DF timer -> start DF wait timer (?)

Section 4

rather than the state of the server states -> rather than the state of
the server (?)

Section 4.2

Si is the IP address of server i -> Si is the IP address of PE i
operator chooses so -> operator so chooses
Note 0 <= i,j <= Number of PEs -- should this be "< Number of PEs"?
Weight(V, Es, Sk) -> Weight(v, Es, Sk)
Pseudo-random -> pseudo-random
efficient deterministic -> efficient and deterministic
V4 -> IPv4
V6 -> IPv6