求教ASR1006出现这些现象是存在环路吗？

惢恨

最近整理设备端口表时，在cdp邻居里看到了设备自己：
ASR1006_02#show cdp nei
Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
ASR1006_02    Ser 0/0/0.1/2/4/1 135              R I   ASR1006   Ser 0/0/0.1/2/4/1:0
ASR1006_02    Ser 0/1/0.1/2/3/2 154              R I   ASR1006   Ser 0/1/0.1/2/3/2:0

端口配置如下，没有配置loopback口：
interface Serial0/0/0.1/2/4/1:0
description to SY
ip address 172.28.198.37 255.255.255.252
cdp enable

使用show interface查看端口状态，存在一个looped：
ASR1006_02#show interface
Serial0/0/0.1/2/4/1:0 is up, line protocol is up (looped)
   Hardware is SPA-1XCHSTM1/OC3
   Description: to SY
   Internet address is 172.28.198.37/30
   MTU 1500 bytes, BW 2048 Kbit/sec, DLY 20000 usec,
      reliability 255/255, txload 1/255, rxload 1/255
   Encapsulation HDLC, crc 16, loopback not set
   Keepalive set (10 sec)
   Last input 00:00:03, output 00:00:03, output hang never
   Last clearing of "show interface" counters 3y3w
   Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 645
   Queueing strategy: fifo
   Output queue: 0/40 (size/max)
   5 minute input rate 6000 bits/sec, 10 packets/sec
   5 minute output rate 6000 bits/sec, 10 packets/sec
      950855908 packets input, 143010908370 bytes, 0 no buffer
      Received 0 broadcasts (0 IP multicasts)
      0 runts, 0 giants, 0 throttles
      1213 input errors, 453 CRC, 314 frame, 0 overrun, 0 ignored, 441 abort
      957263308 packets output, 130711745968 bytes, 0 underruns
      0 output errors, 0 collisions, 106 interface resets
      0 unknown protocol drops
      0 output buffer failures, 0 output buffers swapped out
      20 carrier transitions no alarm present
   VC 30: timeslot(s): UNFRAMED, Transmitter delay 0, non-inverted data

请问这是怎么回事啊？是存在环路吗？但使用中一直没有出现问题啊，CPU占用也很低。