I have a network of Sparcs connected using Suns PPP product and running
the Sun routed. The network can be considered as being arranged thus:
link 1 link 2
| | | |
----- ----- -----
| A | | B | | C |
----- ----- -----
Obviously under normal operation the routing tables route A-B over link1,
B-C over link2 and A-C over link3. In the event of a fault on any single
link then after 180s (routed uses RIP) the routing tables are updated
and a two hop alternative used (i.e. if link3 goes down the A-C has to go
via link1 and then link2).
This all works fine. However I have a few further requirements of which
I have ideas on and some of which I suspect might not be possible.
I would very much appreciate any comments/suggestions/criticism (VIA EMAIL
since we don't have news here :-( ) on the following points:
1) Can I speed the rerouting up? I don't see any way of
changing the RIP packet timings on routed. In fact I
guess the standard dictates these timings. I could
get 'gated' and modify the source... The links are
synchronous (64Kbps) and will ultimately be going
over a 'virtually' error free optical fibre so we
can virtually discount 'packet loss'. The application
requires a bandwidth of about 20Kbps max.
2) When the routing tables are updated any current
connections are obviously still using the old
interface. The application needs to close the (TCP)
connection and connect again. Is there any way
to dynamically change existing connections? Would
it be feasible to change the kernel structures on
the fly to point at the new interface? Does anyone
know of any code that does this?
3) Anybody used OSPF? Does it come close to any of the
above? Is there a freely distributable Unix implementation
What I am trying to achieve is a software equivalent of having fast external
routers. I would welcome any comments or advice (by EMAIL please). I will
summarise to individuals or the net if demand warrants.
James Bridson STC Submarine Systems
Northern Telecom Europe Limited Six Hills House, London Road,
Stevenage, Hertfordshire SG1 1YB