Core switch to Access switch ping issue

ajeet gupta · ‎03-19-2026

I have 9200 as core switch and 2961 as access switch in my LAN. On Core I have SVI 95 and from same subnet I have used IP address for MGMT of access switch.
On interface of core switch, configured native 900 and trunk mode. Same native VLAN and trunk mode is configured on uplink port of access switch.

Some time there is intermittent drops between Core and access switch and some time ping is fully gone.

Kindly note, there are end host who have IP address from same SVI 95 and able to ping user IP address from Core switch.

I'm not seeing any MAC flap/duplicate logs in both Core and access switch. STP showing designated forwarding for VLAN 95

Mark Elsen · ‎03-19-2026

- @ajeet gupta Low level ping is not a determining factor for concluding a problem;
(also) check logs on the switches

M.

-- ' Listen to the wind, it talks
Listen to the silence, it speaks
Listen to your heart, it knows
Ganado Mucho (1809 to 1893 ) Navajo Indian

ajeet gupta · ‎03-19-2026

Log Buffer (4096 bytes):
consistent peer vlan.
082696: .Mar 19 05:39:58.443 UTC: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/49 on VLAN1244. Inconsistent peer vlan.
082697: .Mar 19 05:39:58.443 UTC: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/49 on VLAN1605. Inconsistent peer vlan.
082698: .Mar 19 05:39:59.320 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/49, changed state to up
082699: .Mar 19 05:40:13.441 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0095. Port consistency restored.
082700: .Mar 19 05:40:13.441 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0691. Port consistency restored.
082701: .Mar 19 05:40:13.445 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0900. Port consistency restored.
082702: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0990. Port consistency restored.
082703: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0999. Port consistency restored.
082704: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1201. Port consistency restored.
082705: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1240. Port consistency restored.
082706: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1241. Port consistency restored.
082707: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1242. Port consistency restored.
082708: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1243. Port consistency restored.
082709: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1244. Port consistency restored.
082710: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1605. Port consistency restored.
082711: .Mar 19 07:19:09.077 UTC: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/31: PD removed
082712: .Mar 19 07:19:10.097 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082713: .Mar 19 07:19:11.111 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082714: .Mar 19 07:19:25.858 UTC: %ILPOWER-7-DETECT: Interface Gi1/0/31: Power Device detected: IEEE PD
082715: .Mar 19 07:19:26.850 UTC: %ILPOWER-5-POWER_GRANTED: Interface Gi1/0/31: Power granted
082716: .Mar 19 07:19:32.852 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082717: .Mar 19 07:19:33.851 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082718: .Mar 19 07:19:46.012 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082719: .Mar 19 07:19:47.015 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082720: .Mar 19 07:19:49.972 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082721: .Mar 19 07:19:50.975 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082722: .Mar 19 07:20:21.577 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082723: .Mar 19 07:20:22.580 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082724: .Mar 19 07:20:25.533 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082725: .Mar 19 07:20:26.533 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082726: .Mar 19 08:40:41.970 UTC: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/31: PD removed
082727: .Mar 19 08:40:42.634 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082728: .Mar 19 08:40:43.637 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
Access-Switch# sh clock
.10:05:07.645 UTC Thu Mar 19 2026
Access-Switch#

Access-Switch#sh run int Gig 1/0/49
Building configuration...

Current configuration : 198 bytes
!
interface GigabitEthernet1/0/49
description Trunk to Core-Switch Ten1/1/1
switchport trunk native vlan 900
switchport mode trunk
mls qos trust dscp
spanning-tree guard loop
end
Access-Switch#sh run | s gateway
ip default-gateway 156.5.95.100
Access-Switch#
Access-Switch#show spanning-tree interface GigabitEthernet1/0/49 detail | sec VLAN0095
Port 49 (GigabitEthernet1/0/49) of VLAN0095 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.49.
Designated root has priority 95, address 0087.64fd.6880
Designated bridge has priority 95, address 0087.64fd.6880
Designated port id is 128.53, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
Loop guard is enabled on the port
BPDU: sent 10, received 8079

Access-Switch#ping 156.5.95.100 repeat 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 156.5.95.100, timeout is 2 seconds:
.!!!.!!!!.!!!.!!!!.!!.!!.!!!.!!!!.!!.!!!!.!!!.!!!.!!!.!!!.
Success rate is 74 percent (43/58), round-trip min/avg/max = 1/2/14 ms
Access-Switch#
Access-Switch#sh run int vl95
Building configuration...

Current configuration : 62 bytes
!
interface Vlan95
ip address 156.5.95.25 255.255.255.0
end

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Core-Switch#sh run int vl95
Building configuration...

Current configuration : 179 bytes
!
interface Vlan95
description 3F Data
ip address 156.5.95.100 255.255.255.0
end
Core-Switch#sh cdp nei | sec AS01
Access-Switch
Ten 1/1/1 144 S I WS-C2960X Gig 1/0/49
Core-Switch#sh ip arp | i 156.5.95.25
Internet 156.5.95.25 0 34f8.e7fa.ae41 ARPA Vlan95
Core-Switch#
Core-Switch#ping 156.5.95.25 re 50
Type escape sequence to abort.
Sending 50, 100-byte ICMP Echos to 156.5.95.25, timeout is 2 seconds:
!!!.!!!!.!!!.!!!!.!!!.!!!.!!!.!!!.!!!.!!!!.!!!!.!!
Success rate is 78 percent (39/50), round-trip min/avg/max = 1/2/13 ms
Core-Switch#
Core-Switch#sh run int te1/1/1
Building configuration...

Current configuration : 180 bytes
!
interface TenGigabitEthernet1/1/1
description Trunk to Access-Switch Gi1/0/49
switchport trunk native vlan 900
switchport mode trunk
spanning-tree guard root
Core-Switch#sh spanning-tree vlan 95

VLAN0095
Spanning tree enabled protocol rstp
Root ID Priority 95
Address 0087.64fd.6880
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 95 (priority 0 sys-id-ext 95)
Address 0087.64fd.6880
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p Edge
Gi1/0/2 Desg FWD 20000 128.2 P2p Edge
Gi1/0/3 Desg FWD 20000 128.3 P2p Edge
Gi1/0/4 Desg FWD 20000 128.4 P2p Edge
Gi1/0/6 Desg FWD 2000000 128.6 P2p Edge
Gi1/0/8 Desg FWD 2000000 128.8 P2p Edge
Gi1/0/9 Desg FWD 20000 128.9 P2p Edge
Gi1/0/10 Desg FWD 2000000 128.10 P2p Edge
Gi1/0/11 Desg FWD 2000000 128.11 P2p Edge
Gi1/0/12 Desg FWD 2000000 128.12 P2p Edge
Gi1/0/15 Desg FWD 20000 128.15 P2p Edge
Te1/1/1 Desg FWD 20000 128.53 P2p Peer(STP)
Te1/1/2 Desg FWD 20000 128.54 P2p Peer(STP)
Te1/1/3 Desg FWD 20000 128.55 P2p Peer(STP)
Gi2/0/39 Desg FWD 200000 128.135 P2p Edge
Gi3/0/27 Desg FWD 20000 128.219 P2p Edge
Gi3/0/34 Desg FWD 20000 128.226 P2p Edge
Gi3/0/36 Desg FWD 200000 128.228 P2p Edge
Gi3/0/37 Desg FWD 200000 128.229 P2p Edge
Gi3/0/46 Desg FWD 20000 128.238 P2p Edge
Te3/1/1 Desg FWD 20000 128.245 P2p Peer(STP)
Te3/1/2 Desg FWD 20000 128.246 P2p Peer(STP)
Te3/1/3 Desg FWD 20000 128.247 P2p Peer(STP)
Po1 Desg FWD 10000 128.3049 P2p
Po2 Desg FWD 10000 128.3050 P2p

ajeet gupta · ‎03-19-2026

Hello Mark,

On core switch I don't see any relevant logs, kindly find the logs from Access switch.

Log Buffer (4096 bytes):
consistent peer vlan.
082696: .Mar 19 05:39:58.443 UTC: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/49 on VLAN1244. Inconsistent peer vlan.
082697: .Mar 19 05:39:58.443 UTC: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/49 on VLAN1605. Inconsistent peer vlan.
082698: .Mar 19 05:39:59.320 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/49, changed state to up
082699: .Mar 19 05:40:13.441 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0095. Port consistency restored.
082700: .Mar 19 05:40:13.441 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0691. Port consistency restored.
082701: .Mar 19 05:40:13.445 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0900. Port consistency restored.
082702: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0990. Port consistency restored.
082703: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0999. Port consistency restored.
082704: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1201. Port consistency restored.
082705: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1240. Port consistency restored.
082706: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1241. Port consistency restored.
082707: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1242. Port consistency restored.
082708: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1243. Port consistency restored.
082709: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1244. Port consistency restored.
082710: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1605. Port consistency restored.
082711: .Mar 19 07:19:09.077 UTC: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/31: PD removed
082712: .Mar 19 07:19:10.097 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082713: .Mar 19 07:19:11.111 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082714: .Mar 19 07:19:25.858 UTC: %ILPOWER-7-DETECT: Interface Gi1/0/31: Power Device detected: IEEE PD
082715: .Mar 19 07:19:26.850 UTC: %ILPOWER-5-POWER_GRANTED: Interface Gi1/0/31: Power granted
082716: .Mar 19 07:19:32.852 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082717: .Mar 19 07:19:33.851 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082718: .Mar 19 07:19:46.012 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082719: .Mar 19 07:19:47.015 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082720: .Mar 19 07:19:49.972 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082721: .Mar 19 07:19:50.975 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082722: .Mar 19 07:20:21.577 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082723: .Mar 19 07:20:22.580 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082724: .Mar 19 07:20:25.533 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082725: .Mar 19 07:20:26.533 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082726: .Mar 19 08:40:41.970 UTC: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/31: PD removed
082727: .Mar 19 08:40:42.634 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082728: .Mar 19 08:40:43.637 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
Access-Switch# sh clock
.10:05:07.645 UTC Thu Mar 19 2026
Access-Switch#

Access-Switch#sh run int Gig 1/0/49
Building configuration...

Current configuration : 198 bytes
!
interface GigabitEthernet1/0/49
description Trunk to Core-Switch Ten1/1/1
switchport trunk native vlan 900
switchport mode trunk
mls qos trust dscp
spanning-tree guard loop
end
Access-Switch#sh run | s gateway
ip default-gateway 156.5.95.100
Access-Switch#
Access-Switch#show spanning-tree interface GigabitEthernet1/0/49 detail | sec VLAN0095
Port 49 (GigabitEthernet1/0/49) of VLAN0095 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.49.
Designated root has priority 95, address 0087.64fd.6880
Designated bridge has priority 95, address 0087.64fd.6880
Designated port id is 128.53, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
Loop guard is enabled on the port
BPDU: sent 10, received 8079

balaji.bandi · ‎03-19-2026

Do you have a VTP Setup? Which one acts as the root bridge for the VLAN?

If the end device is working, and the only issue is with the the switch, check the configuration matches both sides:

show interfaces trunk

not only native vlan, but also make sure the vlan is allowed in the allowed list :

interface <uplink_port>
 switchport trunk allowed vlan add 95,900

are you using ip route or ip default gateway on the access switch ?

also check below command : show spanning-tree interface <uplink_port> detail

BB

=====️ Preenayamo Vasudevam ️=====

***** Rate All Helpful Responses *****

How to Ask The Cisco Community for Help

ajeet gupta · ‎03-19-2026

Hello,
Yes, VTP is enabled on Core switch in Transparent mode.
I have configured "ip default-gateway 156.5.95.100".

Kindly find the logs below

Core-Switch#sh run int vl95
Building configuration...

Current configuration : 179 bytes
!
interface Vlan95
description 3F Data
ip address 156.5.95.100 255.255.255.0
end
Core-Switch#sh cdp nei | sec AS01
Access-Switch
Ten 1/1/1 144 S I WS-C2960X Gig 1/0/49
Core-Switch#sh ip arp | i 156.5.95.25
Internet 156.5.95.25 0 34f8.e7fa.ae41 ARPA Vlan95
Core-Switch#
Core-Switch#ping 156.5.95.25 re 50
Type escape sequence to abort.
Sending 50, 100-byte ICMP Echos to 156.5.95.25, timeout is 2 seconds:
!!!.!!!!.!!!.!!!!.!!!.!!!.!!!.!!!.!!!.!!!!.!!!!.!!
Success rate is 78 percent (39/50), round-trip min/avg/max = 1/2/13 ms
Core-Switch#
Core-Switch#sh run int te1/1/1
Building configuration...

Current configuration : 180 bytes
!
interface TenGigabitEthernet1/1/1
description Trunk to Access-Switch Gi1/0/49
switchport trunk native vlan 900
switchport mode trunk
spanning-tree guard root
Core-Switch#sh spanning-tree vlan 95

VLAN0095
Spanning tree enabled protocol rstp
Root ID Priority 95
Address 0087.64fd.6880
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 95 (priority 0 sys-id-ext 95)
Address 0087.64fd.6880
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p Edge
Gi1/0/2 Desg FWD 20000 128.2 P2p Edge
Gi1/0/3 Desg FWD 20000 128.3 P2p Edge
Gi1/0/4 Desg FWD 20000 128.4 P2p Edge
Gi1/0/6 Desg FWD 2000000 128.6 P2p Edge
Gi1/0/8 Desg FWD 2000000 128.8 P2p Edge
Gi1/0/9 Desg FWD 20000 128.9 P2p Edge
Gi1/0/10 Desg FWD 2000000 128.10 P2p Edge
Gi1/0/11 Desg FWD 2000000 128.11 P2p Edge
Gi1/0/12 Desg FWD 2000000 128.12 P2p Edge
Gi1/0/15 Desg FWD 20000 128.15 P2p Edge
Te1/1/1 Desg FWD 20000 128.53 P2p Peer(STP)
Te1/1/2 Desg FWD 20000 128.54 P2p Peer(STP)
Te1/1/3 Desg FWD 20000 128.55 P2p Peer(STP)
Gi2/0/39 Desg FWD 200000 128.135 P2p Edge
Gi3/0/27 Desg FWD 20000 128.219 P2p Edge
Gi3/0/34 Desg FWD 20000 128.226 P2p Edge
Gi3/0/36 Desg FWD 200000 128.228 P2p Edge
Gi3/0/37 Desg FWD 200000 128.229 P2p Edge
Gi3/0/46 Desg FWD 20000 128.238 P2p Edge
Te3/1/1 Desg FWD 20000 128.245 P2p Peer(STP)
Te3/1/2 Desg FWD 20000 128.246 P2p Peer(STP)
Te3/1/3 Desg FWD 20000 128.247 P2p Peer(STP)
Po1 Desg FWD 10000 128.3049 P2p
Po2 Desg FWD 10000 128.3050 P2p

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Log Buffer (4096 bytes):
consistent peer vlan.
082696: .Mar 19 05:39:58.443 UTC: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/49 on VLAN1244. Inconsistent peer vlan.
082697: .Mar 19 05:39:58.443 UTC: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/49 on VLAN1605. Inconsistent peer vlan.
082698: .Mar 19 05:39:59.320 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/49, changed state to up
082699: .Mar 19 05:40:13.441 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0095. Port consistency restored.
082700: .Mar 19 05:40:13.441 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0691. Port consistency restored.
082701: .Mar 19 05:40:13.445 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0900. Port consistency restored.
082702: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0990. Port consistency restored.
082703: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN0999. Port consistency restored.
082704: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1201. Port consistency restored.
082705: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1240. Port consistency restored.
082706: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1241. Port consistency restored.
082707: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1242. Port consistency restored.
082708: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1243. Port consistency restored.
082709: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1244. Port consistency restored.
082710: .Mar 19 05:40:13.448 UTC: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/49 on VLAN1605. Port consistency restored.
082711: .Mar 19 07:19:09.077 UTC: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/31: PD removed
082712: .Mar 19 07:19:10.097 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082713: .Mar 19 07:19:11.111 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082714: .Mar 19 07:19:25.858 UTC: %ILPOWER-7-DETECT: Interface Gi1/0/31: Power Device detected: IEEE PD
082715: .Mar 19 07:19:26.850 UTC: %ILPOWER-5-POWER_GRANTED: Interface Gi1/0/31: Power granted
082716: .Mar 19 07:19:32.852 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082717: .Mar 19 07:19:33.851 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082718: .Mar 19 07:19:46.012 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082719: .Mar 19 07:19:47.015 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082720: .Mar 19 07:19:49.972 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082721: .Mar 19 07:19:50.975 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082722: .Mar 19 07:20:21.577 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082723: .Mar 19 07:20:22.580 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
082724: .Mar 19 07:20:25.533 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to up
082725: .Mar 19 07:20:26.533 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to up
082726: .Mar 19 08:40:41.970 UTC: %ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/31: PD removed
082727: .Mar 19 08:40:42.634 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/31, changed state to down
082728: .Mar 19 08:40:43.637 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/31, changed state to down
Access-Switch# sh clock
.10:05:07.645 UTC Thu Mar 19 2026
Access-Switch#

Access-Switch#sh run int Gig 1/0/49
Building configuration...

Current configuration : 198 bytes
!
interface GigabitEthernet1/0/49
description Trunk to Core-Switch Ten1/1/1
switchport trunk native vlan 900
switchport mode trunk
mls qos trust dscp
spanning-tree guard loop
end
Access-Switch#sh run | s gateway
ip default-gateway 156.5.95.100
Access-Switch#
Access-Switch#show spanning-tree interface GigabitEthernet1/0/49 detail | sec VLAN0095
Port 49 (GigabitEthernet1/0/49) of VLAN0095 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.49.
Designated root has priority 95, address 0087.64fd.6880
Designated bridge has priority 95, address 0087.64fd.6880
Designated port id is 128.53, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
Loop guard is enabled on the port
BPDU: sent 10, received 8079

Access-Switch#ping 156.5.95.100 repeat 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 156.5.95.100, timeout is 2 seconds:
.!!!.!!!!.!!!.!!!!.!!.!!.!!!.!!!!.!!.!!!!.!!!.!!!.!!!.!!!.
Success rate is 74 percent (43/58), round-trip min/avg/max = 1/2/14 ms
Access-Switch#
Access-Switch#sh run int vl95
Building configuration...

Current configuration : 62 bytes
!
interface Vlan95
ip address 156.5.95.25 255.255.255.0
end

Access-Switch#

David Ruess · ‎03-19-2026

It appears you have a spanning tree issue. I would imagine if you fixed that your pings would clean up.

David Ruess · ‎03-19-2026

Hello,

Can you provide the configuration for both devices please?

-David

ajeet gupta · ‎03-19-2026

Core-Switch#sh run int vl95
Building configuration...

Current configuration : 179 bytes
!
interface Vlan95
description 3F Data
ip address 156.5.95.100 255.255.255.0
end
Core-Switch#sh cdp nei | sec AS01
Access-Switch
Ten 1/1/1 144 S I WS-C2960X Gig 1/0/49
Core-Switch#sh ip arp | i 156.5.95.25
Internet 156.5.95.25 0 34f8.e7fa.ae41 ARPA Vlan95
Core-Switch#
Core-Switch#ping 156.5.95.25 re 50
Type escape sequence to abort.
Sending 50, 100-byte ICMP Echos to 156.5.95.25, timeout is 2 seconds:
!!!.!!!!.!!!.!!!!.!!!.!!!.!!!.!!!.!!!.!!!!.!!!!.!!
Success rate is 78 percent (39/50), round-trip min/avg/max = 1/2/13 ms
Core-Switch#
Core-Switch#sh run int te1/1/1
Building configuration...

Current configuration : 180 bytes
!
interface TenGigabitEthernet1/1/1
description Trunk to Access-Switch Gi1/0/49
switchport trunk native vlan 900
switchport mode trunk
spanning-tree guard root
Core-Switch#sh spanning-tree vlan 95

Access-Switch#sh run int Gig 1/0/49
Building configuration...

Current configuration : 198 bytes
!
interface GigabitEthernet1/0/49
description Trunk to Core-Switch Ten1/1/1
switchport trunk native vlan 900
switchport mode trunk
mls qos trust dscp
spanning-tree guard loop
end
Access-Switch#sh run | s gateway
ip default-gateway 156.5.95.100
Access-Switch#

Access-Switch#ping 156.5.95.100 repeat 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 156.5.95.100, timeout is 2 seconds:
.!!!.!!!!.!!!.!!!!.!!.!!.!!!.!!!!.!!.!!!!.!!!.!!!.!!!.!!!.
Success rate is 74 percent (43/58), round-trip min/avg/max = 1/2/14 ms
Access-Switch#
Access-Switch#sh run int vl95
Building configuration...

Current configuration : 62 bytes
!
interface Vlan95
ip address 156.5.95.25 255.255.255.0
end

Access-Switch#

Joseph W. Doherty · ‎03-19-2026

The intermittent ping drops are when you ping the mgmt address of the 2961, on V95, correct?

Other hosts on V95 can ping without issue through the 2961, correct?

Have you tried pinging other hosts on V95, through the 2961? If so, no ping issues?

If the only problem appears to be pinging the 2961, itself, ping response is considered a low priority task on Cisco network devices, and as such, the switch may ignore some or all ping requests.

What's the 2961 CPU history look like, especially at the times of ping loss?

ajeet gupta · ‎03-19-2026

Hello Joseph,

>> The intermittent ping drops are when you ping the mgmt address of the 2961, on V95, correct?:- Yes

>> Other hosts on V95 can ping without issue through the 2961, correct?- I can ping the other host IP without issue from Core switch, from 2961 ping drops pattern is same.

>> Have you tried pinging other hosts on V95, through the 2961? If so, no ping issues?- Yes Ping issue is there while pinging the host IP from 2961. Below I have pasted logs while pinging the host 156.5.95.65 both from Core and access switch. The host is connected to port 1/0/36 of the same access switch.

>> What's the 2961 CPU history look like, especially at the times of ping loss?:- CPU utilization never crossed 50%
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Core-Switch#sh ip arp vlan 95 | i 156.5.95.65
Internet 156.5.95.65 8 805e.0c74.f6f0 ARPA Vlan95
Core-Switch#

Core-Switch#ping 156.5.95.65 re
Core-Switch#ping 156.5.95.65 repeat 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 156.5.95.65, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 1/1/2 ms
Core-Switch#

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Access-Switch#ping 156.5.95.65 repeat 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 156.5.95.65, timeout is 2 seconds:
!!!.!!!!.!!!.!!!!.!!!!.!!!!.!!!.!!!.!!!!.!!!!.!!!!.!!!!!.!!!!.!!!!.!!!
!.!!.!!!!.!!!!.!!!!!.!!!.!!!!.
Success rate is 79 percent (79/100), round-trip min/avg/max = 1/15/1000 ms
Access-Switch#show mac add
Access-Switch#show mac address-table add
Access-Switch#show mac address-table address 805e.0c74.f6f0
Mac Address Table
-------------------------------------------

Vlan Mac Address Type Ports
---- ----------- -------- -----
95 805e.0c74.f6f0 DYNAMIC Gi1/0/36
Total Mac Addresses for this criterion: 1
Access-Switch#
Access-Switch#sh run int gig1/0/36
Building configuration...

Current configuration : 169 bytes
!
interface GigabitEthernet1/0/36
description user access
switchport access vlan 95
switchport mode access
speed 1000
duplex full
spanning-tree portfast edge
end

Access-Switch#