From: Ed Swierk <eswierk@bigswitch.com>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH 2/2] bridge: allow forwarding some link local frames
Date: Mon, 17 Oct 2011 07:35:53 -0700 [thread overview]
Message-ID: <CAF5U64AYRhZ1e0=-RhSemgaOnewTQSpAoRY2FUrFr252PG98Pw@mail.gmail.com> (raw)
In-Reply-To: <20111004041509.292932641@vyatta.com>
Why is forwarding LLDP (01-80-C2-00-00-0E) frames forbidden? I'm
testing LLDP in a virtual topology and need the bridge to forward
them.
If we're worried about standards, there is justification for allowing
forwarding of LLDP frames. 802.1d-2005 specifies two classes of
bridge, customer (C-VLAN) and provider (S-VLAN). Customer bridge is
just new terminology for what was previously just called an
802.1d-compliant bridge, while provider bridge is a new class that
transparently forwards certain control frames.
The only MAC addresses that are not supposed to be forwarded by either
customer or provider bridges are:
IEEE 802.3 Full Duplex PAUSE operation (01-80-C2-00-00-01)
IEEE 802.3 Slow_Protocols_Multicast address (01-80-C2-00-00-02)
IEEE 802.1X PAE address (01-80-C2-00-00-03)
Provider Bridge Group Address (01-80-C2-00-00-08)
Customer bridges are also not supposed to forward these addresses:
Bridge Group Address (01-80-C2-00-00-00)
Provider Bridge GVRP Address (01-80-C2-00-00-0D)
IEEE 802.1AB Link Layer Discovery Protocol multicast address (01-80-C2-00-00-0E)
My application requires a bridge between a pair of interfaces that
forwards (at least) LLDP frames; call this a provider bridge if you
care about standards conformance. It sounds like others require
forwarding 802.1X PAE frames, which appears non-conformant in any
case.
Standards aside, given that the default behavior is safe and that
/sys/class/net/brX/bridge/group_fwd_mask is unlikely to be modified by
accident by a casual user, can we just remove the
BR_GROUPFWD_RESTRICTED mask and allow users to forward whatever they
want?
--Ed
next prev parent reply other threads:[~2011-10-17 14:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111004041444.793960297@vyatta.com>
2011-10-04 4:14 ` [PATCH 1/2] bridge: leave carrier on for empty bridge Stephen Hemminger
2011-10-06 19:28 ` David Miller
2011-10-04 4:14 ` [PATCH 2/2] bridge: allow forwarding some link local frames Stephen Hemminger
2011-10-04 19:11 ` Benjamin Poirier
2011-10-05 19:40 ` Ben Hutchings
2011-10-05 20:50 ` Stephen Hemminger
2011-10-06 19:28 ` David Miller
2011-10-17 14:35 ` Ed Swierk [this message]
2011-10-17 15:18 ` Stephen Hemminger
2011-10-17 20:53 ` Ross Brattain
2011-10-17 21:09 ` Ed Swierk
2011-10-17 23:07 ` Ross Brattain
2011-10-17 23:36 ` Ed Swierk
2011-10-18 0:00 ` John Fastabend
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