Delta Electronics Sonet OC-48/SDH User Manual download pdf (Page 36)

Interface Diagnostic Commands

When an interface is operating in a remote loopback mode, packets received from the physi-

cal circuit and CSU are received by the interface. In addition, those same packets are immedi-

ately retransmitted by the PIC back out toward the CSU and the circuit. This environment is dis-

played in Figure 2.8.

FIGURE 2.8 remote loopback

In our example, Cabernet suspects a physical circuit problem between itself and the far-end

router, so we decide to initiate a loop on Cabernet to test the line. The configuration looks like this:

[edit interfaces t3-1/2/0]

user@Cabernet# set t3-options loopback remote

[edit interfaces t3-1/2/0]

user@Cabernet# show

t3-options {

loopback remote;

}

We now check the interface status:

user@Cabernet> show interfaces t3-1/2/0

Physical interface: t3-1/2/0, Enabled, Physical link is Up

Interface index: 14, SNMP ifIndex: 18

Link-level type: PPP, MTU: 4474, Clocking: Internal

Speed: T3, Loopback: Remote, CRC: 16, Mode: C/Bit parity

Device flags : Present Running

Interface flags: Point-To-Point SNMP-Traps

Link flags : Keepalives

Keepalive settings: Interval 10 seconds, Up-count 1, Down-count 3

Keepalive Input: 7245 (00:00:09 ago), Output: 7281 (00:00:04 ago)

NCP state: Down, LCP state: Conf-req-sent

Input rate : 0 bps (0 pps), Output rate: 0 bps (0 pps)

Active alarms : None

Active defects : None

Logical interface t3-1/2/0.0 (Index 105) (SNMP ifIndex 29)

Flags: Hardware-Down Point-To-Point SNMP-Traps, Encapsulation: PPP

Protocol inet, MTU: 4470, Flags: Protocol-Down

PIC

remote Loopback

CSU

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Delta Electronics Sonet OC-48/SDH User Manual Page 36