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Re: IESG statement on BGP overloading for VPNs
some grammar nits, some things I don't understand.....
--On 15. oktober 2003 23:36 -0700 Alex Zinin <zinin@psg.com> wrote:
Below is the proposed draft text of the IESG statement. Comments
welcome.
Alex
The IESG has been requested to provide its opinion on the issue
of routing protocol overloading as applied to the BGP extensions
proposed for VPN discovery and signaling described in the following
documents:
1. draft-ietf-l2vpn-vpls-bgp
2. draft-ietf-l3vpn-bgpvpn-auto
Consultation with the Routing Area and O&M Area directorates, and the
discussion on the related topics on the Routing Area mailing list,
brought up several concerns:
1. BGP is part of the Internet's critical infrastructure.
Excessive number of BGP applications increases the size of the
^An
BGP code running on the Internet routers, its complexity, memory
and bandwidth requirements for routers, increases the risk of
interference between the IP routing-related BGP code and new
applications, as well as the risk of interference between the
Internet BGP system and its other applications.
2. Routing protocols should not be used as universal transport
mechanisms.
There are two potential ways of using routing protocols to
distribute additional information--using the same protocol
s/additional information/information required for other applications/?????
infrastructure as for regular IP routing (integrated model) and
using a separate independent instance of the protocol with
possible adjustments (parallel model).
Distribution of arbitrary information using the integrated model
has the potential of affecting the convergence characteristics of
the original routing system if the amount of information being
distributed, its growth and change dynamics are such that they
lead to increased consumption of such network resources as router
CPU and link bandwidth. Thus, every new type of information added
to a routing protocol should be carefully considered for possible
effects on the existing routing system.
Potential problems related to the parallel model are less
obvious, since the details of network (and router) resources
separation and process decoupling between the protocol
applications and instances are now hidden behind implementation
specifics. However, one can still identify increased risk of
interference between IP routing and other routing protocol
applications compared to distribution of information using
separate (not routing) protocols.
don't see that in the case of "protocol X" being deployed on separate
hardware; do see it in the case of reusing the same hardware.
3. ????
a very compelling argument :-)
The IESG recommendations are as follows:
1. Following the long-standing practice of hosting the work on
protocol extensions within the WG responsible for the protocol,
the BGP-specific parts of the proposal should be submitted to
the IDR WG and discussed there.
2. Consensus within the IDR WG should be a requirement for
continuing the work on the proposed BGP extensions. It is the
responsibility of the proponents to show why BGP is the right
(and safe) choice for the functionality being addressed, as
opposed to others having to show why the mechanism is broken.
3. If the IDR WG decides that using the MP-BGP framework for
discussed applications is appropriate, the IESG recommends
considering instantiation of a separate protocol, inheriting
the interesting MP-BGP functionality, yet having its evolution.
4. Considering that the MP-BGP framework is already used by multiple
applications (including IPv4, IPv6, unicast and multicast routing),
the IESG recommends that the IDR WG performs the analysis of how
much separation between different AFI/SAFI sets is achievable and
addresses the identified issues where necessary.
I'm not sure we need to force reuse of the BGP protocol formats (such as
was done in TRIP) through the IDR WG.
It seems that what you look for is:
- If the application promoter decides to not use a BGP-like protocol, the
IDR WG will not interfere
- If the application promoter decides to use a BGP-like protocol, the IDR
WG will give advice on whether to integrate it in the regular BGP
deployment framework or instantiate another protocol that "looks like BGP"
- For the "integrated" model, the IDR WG is required to have consensus that
this is OK in order to do it
did I understand it correctly?
Harald