Troubleshooting ERSPAN reachability errors

Follow these examples to troubleshoot and resolve ERSPAN destination not reachable errors. 

device(config)# show erspan profile 1
Profile 1
Type             ERSPAN
Mirror destination Not reachable.
Reason: ***********
Destination IP   10.1.1.100
Destination MAC  0000.0000.0000
Source IP        10.1.1.1
Source MAC       cc4e.0000.0000
Ports monitored:
  Input monitoring      : (U1/M1)   1 
  Output monitoring     : (U1/M1)   1 
HW destination id for each device:
stack_id/device:dest_id

There are seven reasons why a Mirror destination Not reachable error occurs.

Case Reason
1 ARP is not resolved.
2 Route does not exist.
3 Outgoing port is a management port.
4 Outgoing port is a loopback port.
5 Outgoing port is a GRE IP tunnel port.
6 Outgoing port is not known.
7 Outgoing port is a sink port.

Follow these examples to resolve the errors.

Case 1: Problem ARP not resolved

device(config-vif-66)# show erspan 

Profile 1
Mirror destination Not reachable.
Reason: ARP not resolved
Destination IP   10.10.10.4
Destination MAC  0000.0000.0000
Source IP        10.10.10.1
Source MAC       0000.0000.0000
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id

Solution - Configure ARP 

device(config-vif-66)# show arp

Total number of ARP entries: 1
Entries in default routing instance:
No.   IP Address       MAC Address    Type     Age Port   Status
1     10.10.10.4             None     Dynamic  1    v66   Pend

device(config-vif-66)# arp 10.10.10.4 aa.bb.cc ethernet 1/1/5

ADD static arp 10.10.10.4 -> 00aa.00bb.00cc -> 1/1/5 (VRF: 0)

device(config-vif-66)# show erspan profile all

Profile 1
Type             ERSPAN
Mirror destination Reachable.
Destination IP   10.10.10.4
Destination MAC  00aa.00bb.00cc
Source IP        10.10.10.1
Source MAC       748e.f8f9.6d80
Outgoing port    1/1/5
Outgoing VLAN    66
Outgoing VE      66
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id

Note: The ARP can also be obtained by using a ping 10.10.10.4 command.

Case 2: Problem Route not exist

device(config-vif-66)# show ip route

Total number of IP routes: 1
Type Codes - B:BGP D:Connected O:OSPF R:RIP S:Static; Cost - Dist/Metric
BGP  Codes - i:iBGP e:eBGP
OSPF Codes - i:Inter Area 1:External Type 1 2:External Type 2
        Destination      Gateway       Port        Cost    Type Uptime
1       10.10.10.0/24    DIRECT        ve 66       0/0     D    0m48s 

device(config-vif-66)# disable              
SYSLOG: <14> Jan  1 00:02:40 SWDR_8 System: Interface ve 66, state down 

device(config-vif-66)# show erspan profile all

Profile 1
Type             ERSPAN
Mirror destination Not reachable.
Reason: Route not exist
Destination IP   10.10.10.4
Destination MAC  0000.0000.0000
Source IP        10.10.10.1
Source MAC       748e.f8f9.6d80
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id

Solution - Enable the interface (VIF) 

device(config-vif-66)# enable

SYSLOG: <14> Jan  1 00:03:07 SWDR_8 System: Interface ve 66, state up 

device(config-vif-66)# show erspan profile all

Profile 1
Type             ERSPAN
Mirror destination Reachable.
Destination IP   10.10.10.4
Destination MAC  00aa.00bb.00cc
Source IP        10.10.10.1
Source MAC       748e.f8f9.6d80
Outgoing port    1/1/5
Outgoing VLAN    66
Outgoing VE      66
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id

Case 3: Problem Outgoing port is management port

device(config-vif-66)# show erspan profile 1

Profile 1
Type             ERSPAN
Mirror destination Not reachable.
Reason: Outgoing port is management port
Destination IP   10.10.10.4
Destination MAC  0000.0000.0000
Source IP        10.10.10.1
Source MAC       748e.f8f9.6d80
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id 

device(config-vif-66)# show ip route

Total number of IP routes: 2
Type Codes - B:BGP D:Connected O:OSPF R:RIP S:Static; Cost - Dist/Metric
BGP  Codes - i:iBGP e:eBGP
OSPF Codes - i:Inter Area 1:External Type 1 2:External Type 2
        Destination      Gateway       Port        Cost    Type Uptime
1       10.10.10.0/24    DIRECT        e mgmt1     0/0     D    0m2s  
2       40.40.40.0/24    DIRECT        e mgmt1     0/0     D    0m2s

The router for an ERSPAN destination IP can be learned by routing protocols (RIP, OSPF, etc.) or you can configure it statistically using ip route command. The commands disable or enable when run on the port is one way to add or remove routes.

Solution

There is no solution to this problem if you continue to use a management port as the outgoing port. You cannot use an IP address reachable through a management port as an ERSPAN destination.

Case 4: Problem Outgoing port is loopback port

device# show erspan profile 1

Profile 1
Type             ERSPAN
Mirror destination Not reachable.
Reason: Outgoing port is loopback port
Destination IP   10.10.10.4
Destination MAC  0000.0000.0000
Source IP        10.10.10.1
Source MAC       0000.0000.0000
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id   

device# show ip route

Total number of IP routes: 1
Type Codes - B:BGP D:Connected O:OSPF R:RIP S:Static; Cost - Dist/Metric
BGP  Codes - i:iBGP e:eBGP
OSPF Codes - i:Inter Area 1:External Type 1 2:External Type 2
        Destination      Gateway       Port        Cost    Type Uptime
1       10.10.10.0/24    DIRECT        loopback 1  0/0     D    0m39s

Solution

There is no solution to this problem if you continue to use an IP address reachable through a loop back interface. You cannot use an IP address reachable through a loop back interface as an ERSPAN destination.

Case 5: Problem Outgoing port is GRE IP tunnel port

. 

device# show erspan profile 1

Profile 1
Type             ERSPAN
Mirror destination Not reachable.
Reason: Outgoing port is GRE IP tunnel port
Destination IP   11.1.1.2
Destination MAC  0000.0000.0000
Source IP        33.33.33.2
Source MAC       0000.0000.0000
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id  

device(config)# show running-config | begin erspan

monitor-profile 1 type erspan
destination-ip 11.1.1.2
source-ip 33.33.33.2

device# show ip in
Interface     IP-Address    OK?  Method    Status   Protocol   VRF           
Eth mgmt1     10.37.78.91   YES  NVRAM     up       up         default-vrf   
Ve 33         33.33.33.2    YES  NVRAM     down     down       default-vrf   
Ve 44         10.10.10.1    YES  manual    up       up         default-vrf   
Tunnel 1      11.1.1.1      YES  manual    up       up         default-vrf

Solution

There is no solution to this problem if you continue to use an IP address reachable through a tunnel interface. You cannot use an IP address reachable through a tunnel interface as an ERSPAN destination.

Case 6: Problem Outgoing port is not known. 

device# show erspan profile 1

Profile 1
Type             ERSPAN
Mirror destination Not reachable.
Reason: Outgoing port is not known
Destination IP   11.1.1.2
Destination MAC  0000.0000.0000
Source IP        33.33.33.2
Source MAC       0000.0000.0000
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id

Solution - The same as with Case 2: Route not exist

Case 7: Problem Outgoing port is a sink port

device# show erspan profile 1

Profile 1
Type             ERSPAN

Mirror destination Not reachable.
Reason: Outgoing port is a sink port
Destination IP   11.1.1.2
Destination MAC  0000.0000.0000
Source IP        33.33.33.2
Source MAC       0000.0000.0000
Ports monitored:
HW destination id for each device:
stack_id/device:dest_id

Solution - The same as with Case 2: Route not exist.

Parent topic: Configuring an ERSPAN Profile