- 1. Opening and Administrivia
- Willem van der Scheun, Chairman, presided and welcomed people to the
meeting. There were 89 attenders. Mike Norris took minutes.
- 2. Agenda bashing
- A draft agenda of business, circulated by the Chairman in the previous
week, was agreed.
- 3. Chairman of the Routing WG
- Willem announced that his day job prevented him from devoting the time
necessary to chairmanship of the WG and that he was standing down. He was
pleased to say that Joachim Schmitz would accept his proposal to be Chairman,
and this proposal was endorsed by the meeting. Members thanked Willem for his
work as Chairman and guidance of the WG. Joachim chaired the remainder of the
meeting.
- 4. Report from the RIPE NCC
- Daniel Karrenberg said that the RIPE NCC planned to resume its studies of
route aggregation. An exercise he had conducted earlier in 1996 and reported to
RIPE 24 had revealed plenty of room for improvement. Individual reports to
those responsible for over-specific routing had resulted in significant
improvements. Since then, however, the aggregation situation had disimproved.
Daniel's impression was that some ISPs didn't care or wouldn't take the trouble
to correct matters.
Further remedial action was needed and the Contributors'
Committee supported the NCC in this work. Skilled staff would soon be appointed
and they would help ISPs in promoting route aggregation. While neither RIPE nor
the NCC could take action against any offenders, the use of peer pressure among
the ISPs could be used in a positive manner to improve the position.
The meeting encouraged ISPs to supply BGP data to the NCC on request for
the purpose of analysing route aggregation.
New Action: the NCC would report on route aggregation at RIPE 26.
- 5.
Working Experience with Route Object Editor (ROE)
- Joachim Schmitz reported on his experience with ROE. This was part of the
RA Toolset and had been written by Cengiz Alaettinoglu. Its purpose was to view
and manipulate route objects and to compare them with operational routes. It
worked on routes as objects from Internet routing registries (IRRs) and as
determined from routers (by means of input BGP tables).
Compiled with C++ in
a Tcl/Tk environment, ROE was easy to install. With its GUI it was easy to use.
As not all IRRs were aligned in the way they worked, ROE displayed separate
route registrations where appropriate.
Joachim found it slow in operation, although Cengiz later indicated that
this was probably due to network and server performance and not to the ROE
program execution. It was also not clear to Joachim whether live or mirrored
IRR data was used.
He suggested that the program could be improved by allowing more
configuration options and greater clarity in some of the messages. This and
other feedback should be directed to Cengiz.
Overall, he recommended ROE for operational use, particularly for complex
routing tasks.
- 6.
Progressive BGP route flap dampening
- Tony Barber gave a presentation on the strategies used by UUnet-Pipex to
reduce the effects of route flapping and to try to prevent router table
overflow. These were:
- route dampening
- prefix filtering
- more router memory
They had encountered many instabilities from peers and found that many ISPs
had not deployed CIDR; this gave rise to more flapping as more routes, and
particularly more specific ones, were advertised.
Tony explained the parameters used for route dampening on a Cisco router.
He had arrived at the following re-use times for various route sizes:
/24 and greater
|
~160 minutes
|
/23 and /22
|
~60 minutes
|
/21 and less
|
~30 minutes
|
He recommended filtering out all prefixes more specific than /24.
While route dampening consumed router memory, this was more or less
balanced by a reduction in routing CPU cycles.
He recommended that if route dampening was to be widely deployed in Europe,
consistency was important. In this sense, the Routing WG should agree on
guidelines for parameters to be used.
In discussion, the following points were made:
- aggregation works in reducing router load and route flapping.
- route flapping is often a feature of certain autonomous systems rather than
a function of prefix length.
- much instability was due to configuration changes and errors as distinct
from link failures.
- making dampening dependent on prefix length could penalise many stable
/24s.
- it might be useful to discriminate against /24s in the 192.0.0.0/8 block
(the swamp).
- the focus should be on keeping noise out of the system rather than trying
to mitigate against it once in the system.
In summary, it was agreed that route dampening was an important topic and
that more discussion was needed.
- 7. Routing Policy analysis
tools
- Cengiz Alaettinoglu of ISI presented a review of recent developments and
updates in the RA toolset, now at version 3.4.0.
The set of front-end tools
used a number of back-end libraries, which made program development easier. It
required RAWhoisd v3.0 and had been ported to several operating systems. Cengiz
gave details of availability (official reference) and of the
mailing list (ratoolset@isi.edu, subscription via robot majordomo@isi.edu). The
toolset was made available for demonstration purposes to attenders of RIPE 25.
RtConfig generated the BGP access list part ofrouter configuration from
route objects. It was now used in production by some major network operators.
ROE was again shown, with reference to review options before submitting a
changed route object.
The AS object editor (AOE) was not implemented, though it was on demo at
RIPE 25.
CIDRAdvisor identifies 'safe' aggregates by route originators as well as
aggregates for proxies. Cengiz showed the effects of using various radius
values for the distance that aggregation should hold.
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