eXR : Default Management Interface Mapping

Question

We dont see second management interface on ASR-9901.

               Intf       Intf        LineP              Encap  MTU        BW

               Name       State       State               Type (byte)    (Kbps)

--------------------------------------------------------------------------------

                Nu0          up          up               Null  1500          0

    Mg0/RSP0/CPU0/0          up          up               ARPA  1514    1000000

          Gi0/0/0/0          up          up               ARPA  1514    1000000

Answer

In eXR one MgmtEth is available to XR VM and the other MgmtEth interface to Admin VM.

CLI Output

P/0/RSP1/CPU0:ASR-9904-eXR#show interfaces brief | i Mg

Thu Oct 10 08:07:37.708 HKT

    Mg0/RSP0/CPU0/0          up          up               ARPA  1514     100000

    Mg0/RSP1/CPU0/0        down        down               ARPA  1514    1000000

RP/0/RSP1/CPU0:ASR-9904-eXR#admin

Thu Oct 10 08:07:42.689 HKT

syzaidi connected from 127.0.0.1 using console on sysadmin-vm:0_RSP0

sysadmin-vm:0_RSP0# show interface ?

Description: Management Interfaces

Possible completions:

  MgmtEth0/RSP0/0/0

  MgmtEth0/RSP1/0/0

  |                   Output modifiers

  <cr>

sysadmin-vm:0_RSP0# show interface

FAQs:

1) Can I configure the mgmt interface in admin VM? 

Yes, it can be configured with an ip address as follows: 

sysadmin-vm:0_RSP0(config)# int MgmtEth 0/RSP0/0/0 ?
Possible completions:
  arp          Configure static ARP entry
  default-gw   Default Gateway address: A.B.C.D
  ipv4         IPv4 parameters
  mtu          MTU for interface
  shutdown     Shut the interface down
  <cr>         
sysadmin-vm:0_RSP0(config)# 

2) Can I use this mgmt ip for telnet/ ssh or out of band access? 

No, this interface is not exposed to the outside world. 

3) What is the purpose of the mgmt interface in admin VM? 

This interface can be used to copy files from router to external loc using mgmt. interface.

4) If a user shuts the mgmt interface in the admin VM down, will we lose the access to the admin VM? 

No, shutting down the interface doesn't block the access to the admin VM, please check below: 

sysadmin-vm:0_RSP0(config)# interface MgmtEth 0/RSP0/0/0
Wed Mar  31 19:20:15.547 UTC+00:00
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# shut 
Wed Mar  31 19:20:19.472 UTC+00:00
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# commit
Wed Mar  31 19:20:22.438 UTC+00:00
Commit complete.
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# 
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# 
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# exit
Wed Mar  31 19:20:25.529 UTC+00:00
sysadmin-vm:0_RSP0(config)# exit
Wed Mar  31 19:20:27.353 UTC+00:00
sysadmin-vm:0_RSP0# 
sysadmin-vm:0_RSP0# 
sysadmin-vm:0_RSP0# sh int
Wed Mar  31 19:20:29.235 UTC+00:00
MgmtEth0/RSP0/0/0  Link encap: Ethernet  HWaddr 02:b3:90:92:72:98
  inet  addr: 0.0.0.0
  DOWN BROADCAST MULTICAST   MTU:1500  Metric:1    <<< port is down. 
  RX packets:          0 errors:0 dropped:0 overruns:0   frame:0
  TX packets:          5 errors:0 dropped:0 overruns:0 carrier:0
                         collisions:0 txqueuelen:1000
  RX bytes:                     0  TX bytes:                   398

sysadmin-vm:0_RSP0# exit
Wed Mar  31 19:20:34.518 UTC+00:00
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#admin
Wed Mar 31 19:20:36.732 UTC

saavadha connected from 127.0.0.1 using console on sysadmin-vm:0_RSP0
sysadmin-vm:0_RSP0# exit  <<< we are still able to connect to the admin VM.
Wed Mar  31 19:20:41.461 UTC+00:00
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#conf t
Wed Mar 31 19:20:44.587 UTC
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1(config)#exit   
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#admin conf
Wed Mar 31 19:21:03.263 UTC
Mar 31 19:21:03 : ADMIN-CLI: ERROR: ABORT: Please run this command from admin prompt
RP/0/RSP0/CPU0:ASR-9904-E-eXR_NPE1#admin
Wed Mar 31 19:21:05.319 UTC

saavadha connected from 127.0.0.1 using console on sysadmin-vm:0_RSP0
sysadmin-vm:0_RSP0# con
Possible completions:
  config       Manipulate software configuration information
  controller   Access to hardware controller data
sysadmin-vm:0_RSP0# config 
Wed Mar  31 19:21:09.125 UTC+00:00
Entering configuration mode terminal
sysadmin-vm:0_RSP0(config)# interface MgmtEth 0/RSP0/0/0
Wed Mar  31 19:21:19.887 UTC+00:00
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# no shut
Wed Mar  31 19:21:21.662 UTC+00:00
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# commit
Wed Mar  31 19:21:23.798 UTC+00:00
Commit complete.
sysadmin-vm:0_RSP0(config-MgmtEth-0/RSP0/0/0)# exit
Wed Mar  31 19:21:25.293 UTC+00:00
sysadmin-vm:0_RSP0(config)# exit
Wed Mar  31 19:21:26.162 UTC+00:00
sysadmin-vm:0_RSP0# 
sysadmin-vm:0_RSP0# 
sysadmin-vm:0_RSP0# sh int
Wed Mar  31 19:21:27.967 UTC+00:00
MgmtEth0/RSP0/0/0  Link encap: Ethernet  HWaddr 02:b3:90:92:72:98
  inet  addr: 0.0.0.0
  UP RUNNING BROADCAST MULTICAST   MTU:1500  Metric:1
  RX packets:          0 errors:0 dropped:0 overruns:0   frame:0
  TX packets:         11 errors:0 dropped:0 overruns:0 carrier:0
                         collisions:0 txqueuelen:1000
  RX bytes:                     0  TX bytes:                   906

sysadmin-vm:0_RSP0#