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Author Topic: Nodes detected on the Uplink  (Read 4446 times)

dekdek

  • Guest
Nodes detected on the Uplink
« on: September 16, 2009, 05:17:59 PM »
i would like to understand one thing, please :
why (and how) a node is discovered (and then seen) on interface which is directly connected and
not on the link interface on the core switch ?
how do you make it dear rickli ?
because i have a problem on one link : some of nodes are discovered on the uplink (core switch) and
others are discovered on their real interface on the real switch. I don't understand this case and don't know
how to solve it.
thank U in advance. 

gumba

  • Guest
Re: Nodes detected on the Uplink
« Reply #1 on: September 17, 2009, 07:26:29 AM »
We had the problem here that nodes, that had a static entry in the mac address table of the access switch they where connected to, were discovered by NeDi to be connected to the uplink interface of the next distribution switch. This is because NeDi ignores static mac address entries (don't know why).
I fixed this by changing line 39 in libcli-netssh.pl from
Code: [Select]
$cmd{'IOS'}{'macd'} = 'sh mac-address-table dyn';
to
Code: [Select]
$cmd{'IOS'}{'macd'} = "sh mac-address-table dyn\nsh mac address-table static";
and line 323 from
Code: [Select]
if ($l =~ /\s+(dynamic|forward|secure(dynamic|sticky))\s+/i){
to
Code: [Select]
if ($l =~ /\s+(static|dynamic|forward|secure(dynamic|sticky))\s+/i){
to have NeDi discover static entries, too.
Maybe this is related to your problem.

dekdek

  • Guest
Re: Nodes detected on the Uplink
« Reply #2 on: September 17, 2009, 08:15:42 AM »
interesting... but i don't use cli options to discover mac_adress_table. Core switch
is a nortel 8600 and i choose to use just SNMP to discover.
In my problem, sometimes a Nodes can be discovered on the right (real) interface and on the next
scan discovered on the uplink on the access switch. Disapointed. Maybe due to the total of nodes
discovered on this particular link ( sometimes < 5 ) and Nedi says 'its not a link, but a node directly
attached. ???

gumba

  • Guest
Re: Nodes detected on the Uplink
« Reply #3 on: September 17, 2009, 08:21:15 AM »
If the node is discovered on the switch's uplink interface, is it still listed in NeDi as a node or as a device? Is there any special configuration on the port the node is connected to?

dekdek

  • Guest
Re: Nodes detected on the Uplink
« Reply #4 on: September 17, 2009, 09:46:11 AM »
still see as a node and nothin special on the port. Here's the view of a Node Status / If Changes.
A_Passport8610 is the core switch and slot1, port 21 the link which device B_ERS2550_v16 is connected.
In this example the node is directly connected to the slot 3, Port 36 of this device.
any idea. thank u so much.

1   11.Sep 09 0:00    A_Passport8610   Slot 1, Port 21   
2   11.Sep 09 9:00    B_ERS2550_v16   ifc164 (Slot: 3 Port: 36)
3   11.Sep 09 19:00    A_Passport8610   Slot 1, Port 21
4   12.Sep 09 14:00    B_ERS2550_v16   ifc164 (Slot: 3 Port: 36)
5   12.Sep 09 15:00    A_Passport8610   Slot 1, Port 21
6   12.Sep 09 17:00    B_ERS2550_v16   ifc164 (Slot: 3 Port: 36)
7   15.Sep 09 20:00    A_Passport8610   Slot 1, Port 21
8   15.Sep 09 21:00    B_ERS2550_v16   ifc164 (Slot: 3 Port: 36)
9   15.Sep 09 23:00    A_Passport8610   Slot 1, Port 21
10   16.Sep 09 13:00    B_ERS2550_v16   ifc164 (Slot: 3 Port: 36)
11   16.Sep 09 17:00    A_Passport8610   Slot 1, Port 21
12   17.Sep 09 0:00    B_ERS2550_v16   ifc164 (Slot: 3 Port: 36)

gumba

  • Guest
Re: Nodes detected on the Uplink
« Reply #5 on: September 17, 2009, 10:05:00 AM »
How is the node seen in the mac address table of the access switch (B_ERS2550_v16)? Could you run 'show mac-address-table' (or whatever the Nortel counterpart of this is) and post the line where the mac address of the node is listed?

dekdek

  • Guest
Re: Nodes detected on the Uplink
« Reply #6 on: September 17, 2009, 11:41:52 AM »
i remember a detail maybe the right track ?
between the core switch (Passport) and the B_ERS2550 there is a fiber media adapter
which is in fact a mini switch with arp table (because it make also speed adpater 100Mb-->1000Mb).
And this is the only place on the lan where i have installed this type of equipment.
but i don't understand why ?

gumba

  • Guest
Re: Nodes detected on the Uplink
« Reply #7 on: September 17, 2009, 11:46:13 AM »
Is this fiber media adapter transparent to the switches or does it appear in the switches' mac address tables? Is it discovered by NeDi?

dekdek

  • Guest
Re: Nodes detected on the Uplink
« Reply #8 on: September 17, 2009, 02:23:56 PM »
don't seem to appear in mac adress table... but i'm not sure with the mac adress of the fiber adapter. i must go in this building tomorrow and i 'll note the mac address beside. i'm just sure it does not have SNMP agent.

gumba

  • Guest
Re: Nodes detected on the Uplink
« Reply #9 on: September 17, 2009, 02:47:44 PM »
What you may check else is the time to live for mac address entries on both switches. If there is low traffic from the node, it may not appear on the access switch any more when NeDi scans, but still be present on the mac table of the core switch due to greater time to live value.
Just a guess.

dekdek

  • Guest
Re: Nodes detected on the Uplink
« Reply #10 on: September 17, 2009, 03:17:11 PM »
ok i will check your guess.
nice talkin with you.
thanks