Wireshark-users: Re: [Wireshark-users] monitor an STM-1 link
From: Tamás Varga <[email protected]>
Date: Mon, 9 Jun 2008 15:13:33 +0200
Title: [Wireshark-users] monitor an STM-1 link
Hi John,
the case is, that for monitoring purpose, both forward and backward link direction has to be connected to an Rx port on the monitoring device, otherwise the monitor device would influence the original traffic through the Tx port that we definitely do not want.

 From: [email protected] [mailto:[email protected]] On Behalf Of Sheahan, John
Sent: Monday, June 09, 2008 14:56
To: Community support list for Wireshark; [email protected]
Subject: Re: [Wireshark-users] monitor an STM-1 link

if you are using a passive tap, you should be able to maintain bidirectional connectivity on the STM-1 and the link should have come back up. Perhaps you're tap is not passive?

From: [email protected] on behalf of Tamás Varga
Sent: Mon 6/9/2008 8:25 AM
To: [email protected]
Subject: [Wireshark-users] monitor an STM-1 link

Hi Experts,

we want to monitor the traffic of an STM-1 (OC-3) link
between two Cisco LS1010 ATM switches. For this purpose,
we put an optical splitter in both forward and backward
direction that produces -26 dBm signal level on the
monitored link. The receiver sensitivity on the monitor
device is stated to be -28 dBm. The receiver link on
the monitor node does not go up (after administrative shut
down is disabled).

Questions, if someone has experience:
- is it possible to force link up even no Tx I/F connected?
- does STM-1 need to have bidirectional connectivity?

 +---------+                                      +---------+
 |        Tx-----------------T--------(dampener)->Rx        |
 | LS1010  |                 |                    |  LS1010 |
 |        Rx<--(dampener)----------T--------------Tx        |
 +---------+                 |     |              +---------+
                             |     |
                             v     v
                         |Tx Rx Tx Rx|
                         |           |
                         |  Monitor  |
                         |  LS1010   |

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