[HECnet] Network topology according to MIM.
Johnny Billquist
bqt at softjar.se
Thu Jan 14 19:33:50 PST 2016
On 2016-01-15 04:28, Johnny Billquist wrote:
> On 2016-01-15 04:18, Robert Armstrong wrote:
>> As Peter said, HECnet isn't really optimized for performance.
>
> In a way that is true. It's not optimal, if we talk about getting data
> travelling the most optimal path. But tries to be very efficient at not
> using much computing resources. Different parameters for "optimized for
> performance", and all that...
>
> It does do optimal pack routing between routing nodes within an area.
> And it do optimal routing of packets between areas. It is the border
> line between endnode and router, and the ingress and egress to areas
> where it is just plain stupid.
Oh, and I didn't pay attention to what you wrote, so I commented on DECnet.
HECnet as such is not optimized either, but at the same time, it very
much depends on how you have done things. For me, hecnet performance
couldn't be better. I had to do throttling of HECnet because otherwise
it just killed DECnet performance on a real 11/93 here... (which is why
the bridge has such functionality, in case anyone ever wondered).
DECnet does *not* deal gracefully with massive packet loss. :-/
Performance really goes down the drain. Doing morse with a flashlight
bouncing off the moon will be faster.
I have never been that happy with having every bridge connect directly
to Update. When I wrote the thing, I really did envision there being
several hubs connected together, and then people connecting to a hub
close to them. Which would have been much better from a performance
point of view. But noone else ever expressed an interest in actually
doing this. And at the same time, bandwidth around much of the world is
good enough nowadays that it's not really an issue.
Johnny
>
>> There's a joke about a Great Dane playing flyball (if you know
>> anything about dog sports, you'll understand) - the amazing thing is
>> not so much that he does it well, but rather that he does it at all.
>>
>> HECnet is a little like that.
>
> That HECnet works is not really that much of a trick.
>
> And I just realized I think I can see what 1.1023 has for cost of the
> link to area 59, and I suspect the cost is 10... Which would mean I'd
> really have to bump the cost of the IP link up a lot to move over to
> that one. :-) At least some other links out from 1.1023 have a cost of 10.
>
> Johnny
>
>>
>> Bob
>>
>> On Jan 14, 2016 19:11, Johnny Billquist <bqt at softjar.se> wrote:
>>>
>>> On 2016-01-15 04:05, Robert Armstrong wrote:
>>>> What happens if you make the cost on the LEGATO link 2 instead of 1?
>>>>
>>>> The cost on my Multinet links are all set to 2. Since your current
>>>> LEGATO cost is 1, the total cost of that path to area 59 is 3. The
>>>> exactly equals the cost on you UNA circuit. In the case of a tie on
>>>> cost, DECnet picks the router with the lowest numerical address,
>>>> hence LEGATO wins.
>>>>
>>>> But if you up the IP-0-0 cost to 2, the total would become 4 and the
>>>> UNA would win.
>>>
>>> Yes, that would be correct.
>>>
>>> I'm still trying to decide which link to prefer, though...
>>>
>>> The problem is partly that this probably depends on how area 59 looks
>>> inside, and which link 1.1023 is using. Am I mostly talking to nodes
>>> close to the next hop from Legato, then the current setup is maybe best.
>>> If I mostly talk to nodes close to the next hop from 1.1023, then it
>>> makes sense to change this...
>>>
>>> Johnny
>>>
>>>>
>>>> Bob
>>>>
>>>> On Jan 14, 2016 18:52, Johnny Billquist <bqt at softjar.se> wrote:
>>>>>
>>>>> Just FYI. It is slightly interesting and informing:
>>>>>
>>>>> 15-JAN-16 03:44:30 Node: MIM (1.13) "RSX system at Update, Sweden"
>>>>> RSX-11M-Plus, Area Routing Node, DECnet V4.6
>>>>> Area Circuit Hop/Cst Next Node Area Circuit Hop/Cst Next
>>>>> Node
>>>>> 2 IP-0-0 1/1 LEGATO( 2.1)
>>>>> 3 IP-0-0 2/3 LEGATO( 2.1)
>>>>> 7 UNA-0 2/7 SG1 (19.41)
>>>>> 8 UNA-0 1/3 GORVAX( 8.400)
>>>>> 12 UNA-0 2/13 ( 1.1023)
>>>>> 14 UNA-0 1/3 SKHNGW(14.4)
>>>>> 18 IP-0-0 2/3 LEGATO( 2.1)
>>>>> 19 UNA-0 1/3 SG1 (19.41)
>>>>> 22 UNA-0 2/23 HUB (42.1022)
>>>>> 23 UNA-0 2/13 ( 1.1023)
>>>>> 33 IP-0-0 2/3 LEGATO( 2.1)
>>>>> 39 IP-0-0 2/3 LEGATO( 2.1)
>>>>> 42 UNA-0 1/3 HUB (42.1022)
>>>>> 44 UNA-0 1/3 A44RTR(44.1023)
>>>>> 59 IP-0-0 2/3 LEGATO( 2.1)
>>>>> 61 UNA-0 2/23 HUB (42.1022)
>>>>> 62 UNA-0 1/3 CTAKAH(62.637)
>>>>> - Total areas: 17-
>>>>>
>>>>> Notice the number of areas that MIM now decided should go over IP-0-0,
>>>>> which is the link to LEGATO. Since I set the cost for that link to 1,
>>>>> while ethernet is at 3, it is rather favored. Not sure it really makes
>>>>> sense to route packets to area 59 that way, since going over
>>>>> ethernet, I
>>>>> would have a direct ptp to area 59 through a Cisco router sitting
>>>>> right
>>>>> next to MIM, but that then becomes a question of what the cost of the
>>>>> link between 1.1023 and area 59 is set to.
>>>>>
>>>>> Johnny
>>>>>
>>>>> --
>>>>> Johnny Billquist || "I'm on a bus
>>>>> || on a psychedelic trip
>>>>> email: bqt at softjar.se || Reading murder books
>>>>> pdp is alive! || tryin' to stay hip" - B. Idol
>>>>>
>>>
>>>
>>> --
>>> Johnny Billquist || "I'm on a bus
>>> || on a psychedelic trip
>>> email: bqt at softjar.se || Reading murder books
>>> pdp is alive! || tryin' to stay hip" - B. Idol
>>>
>
>
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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