For many years I have configured HSRP on my IOS based devices with tracking configured for a Loopback without an IP so that during maintenance windows one simply needs to down the loopback to fail HSRP to the peer. However, recently when configuring the same setup on an ASR9K, I noticed that while the loopback shows up/up, HSRP sees it as down (config/output below). The only way to get HSRP to see the loopback as up is by configuring an IP on the loopback.
Does anyone know if this is intentional/expected behavior? Again, in IOS and NX-OS you do not need an IP on the loopback for HSRP to see it as up and track accordingly.
Thanks!
RP/0/RSP0/CPU0:ASR9K#sh int lo192
Tue Jun 12 22:18:47.134 MST
Loopback192 is up, line protocol is up
Interface state transitions: 1
Hardware is Loopback interface(s)
Description: HSRP Tracking - DO NOT DOWN
Internet address is Unknown
MTU 1500 bytes, BW Unknown
reliability Unknown, txload Unknown, rxload Unknown
Encapsulation Loopback, loopback not set,
Last input Unknown, output Unknown
Last clearing of "show interface" counters Unknown
Datarate information unavailable.
Interface counters unavailable.
RP/0/RSP0/CPU0:ASR9K#sh run router hsrp
Tue Jun 12 22:18:47.134 MST
router hsrp
interface TenGigE0/0/0/2
hsrp 1 track Loopback192 200
hsrp 1 preempt
hsrp 1 ipv4 X.X.X.X
hsrp 1 priority 255
RP/0/RSP0/CPU0:ASR9K#sh hsrp te0/0/0/2 det
Tue Jun 12 22:18:53.054 MST
TenGigE0/0/0/2 - Group 1
Local state is Standby, priority 55, may preempt
Hellotime 3 sec holdtime 10 sec
Minimum delay 1 sec, reload delay 5 sec
Hot standby IP address is X.X.X.X configured
Active router is X.X.X.Y, priority 100 expires in 00:00:07
Standby router is local
Standby virtual mac address is 0000.0c07.ac01
6 state changes, last state change 00:12:18
State change history:
Jun 12 22:05:59.547 MST Init -> Listen Delay timer expired
Jun 12 22:06:09.549 MST Listen -> Speak Active timer expired
Jun 12 22:06:19.551 MST Speak -> Standby Standby timer expired
Jun 12 22:06:19.551 MST Standby -> Active Active timer expired
Jun 12 22:06:24.195 MST Active -> Speak Higher priority active received
Jun 12 22:06:34.197 MST Speak -> Standby Standby timer expired
Last coup sent: Never
Last coup received: Jun 12 22:06:24.209 MST
Last resign sent: Jun 12 22:06:24.195 MST
Last resign received: Never
Tracking interface states for 1 interface, 0 up:
Down Loopback192 Priority decrement: 200
