ScreenOS Firewalls (NOT SRX)
ScreenOS Firewalls (NOT SRX)

T1 card question

‎10-13-2011 10:07 AM

I have a dual T1 card in my SSG520.  Currently we're having bouncing issues on the circuit, and the provider (qwest) wants to loop up the circuit, but they're saying they can't reach it.


On the WAN tab, the setting for "Loopback Mode" is none - do i need to change this setting so the provider can loop it up?  If so, is the change only for the duration of the test, or would this be a permanent setting change.





ScreenOS Firewalls (NOT SRX)

Re: T1 card question

‎10-14-2011 04:06 AM

When the carrier wants to loop the circuit they essentially are testing the ability of their own equipment and taking your firewall out of the mix.  You are "looping" the carrier in to the carrier out lines and they make sure there are no errors.  Typically this is done with a physical plug into the smart jack.


See this diagram.


What this setting does on the T1 PIM is create this same loop at the jack of your firewall.  This is good because you will also be testing the cable that connects your smart jack to the interface.  So it will verify the entire cable plant and the only item NOT under test is the T1 card.  So if the circuit comes up clean the issue will be with the T1 card or programming.


The cirucuit does not work on the SSG during loop mode.  You will not have access to this circuit once you enable loop mode.  So you need to have an alternate path to turn this on/off for the test period.

Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)