[HECnet] "Dropped by adjacent node" ....

[Paul_Koning at Dell.com]

On May 25, 2014, at 9:33 PM, Johnny Billquist <bqt at softjar.se> wrote:

On 2014-05-26 03:06, Bob Armstrong wrote:
Do you have a max routers set too low on your machine maybe?
We have quite a few routers on the bridge segment.

$ NCP SHOW EXEC CHAR
...
Max broadcast nonrouters = 512
Max broadcast routers       = 128
...

$ NCP TELL MIM SHOW EXEC CHAR
...
Max broadcast nonrouters = 64
Max broadcast routers       = 20
...

  Maybe it's too low on MIM??   The message actually makes it sound like MIM
is dropping LEGATO, not the other way around.

Could be... In fact you are probably right. Just checked, and MIM have a MAX of 20 right now, which I believe is too low here. Increased it to 32, but I need to reboot for it to take effect   

In DECnet, we do not assume that    I can hear A    means    A can hear me   .   Instead, the protocol explicitly tests for that (in the case of routers).   If the test fails, you don   t get an adjacency.   If there was an adjacency before, and then the test fails, that adjacency goes down.

The way this is done is that the Ethernet router hello message contains a list of routers the sender has heard.   If a router doesn   t see itself listed, it doesn   t bring up the adjacency with the sender of that router hello.   If it was there and goes away, you get the    dropped by adjacency router    event.

To find out why the adjacent router stopped mentioning you, you need to look in its event log.   If the reason is too many router, there should be an event that says so.   If the reason is something else, the reason should say what else it is.   For example, it might be    adjacency listener timeout    meaning no hello messages were seen in 3 * hello time.

	paul