4G LTE Cellular configuration VRF / source interface issue

[perkin]

Hello my friends

I am pretty new to 4G card connection, recently we get a module NIM-4G-LTE-GA, put a sim card and google some basic setup from internet/cisco, and it works, we even made that works with the TCL script with SMS  control too.

after the Fancy functions, we test, and in the actual head to head configuration, the internet seems to me that some command they are not compatible say, for example, the source Ping also the VRF (we are using DMVPN with VRF) setup.

first, if I issue
#ping 8.8.8.8 so C0/1/0

It NOT work ping said this internet is not enabled or DOWN

but when I issue

#ping 8.8.8.8

it missed 2 ping then the interface is up , then I can run #ping 8.8.8.8 so C0/1/0 without issue!

also this is the simialr issue when I do VRF forwarding on this C0/1/0 interface,it seems VRF think this interface is down and not allow me to ping via #ping vrf TRANSPORT 8.8.8.8

that is not make sense for me, I guess is that some basic cli can keep the Cell interface always UP?

test-rtr#sh hw-module subslot all oir
Module Model Operational Status
------------- -------------------- ------------------------
subslot 0/0 ISR4321-2x1GE ok
subslot 0/1 NIM-4G-LTE-GA ok

test-rtr#

test-rtr#sh ver | i ers
Cisco IOS XE Software, Version 16.09.03

test-rtr#
est-rtr#sh run int c0/1/0
Building configuration...

Current configuration : 100 bytes
!
interface Cellular0/1/0
ip address negotiated
dialer in-band
dialer-group 1
pulse-time 1
end

test-rtr#sh run | i ip route
ip route 0.0.0.0 0.0.0.0 Cellular0/1/0

ip route vrf TRANSPORT 0.0.0.0 0.0.0.0 Cellular0/1/0
test-rtr#ping 8.8.8.8 so c0/1/0
% Invalid source interface - IP not enabled or interface is down
PKF-test-rtr#ping 8.8.8.8
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:
..
*Jul 10 11:19:54.389: %LINK-3-UPDOWN: Interface Cellular0/1/0, changed state to up.!!
Success rate is 40 percent (2/5), round-trip min/avg/max = 61/155/249 ms
test-rtr#
*Jul 10 11:19:55.389: %LINEPROTO-5-UPDOWN: Line protocol on Interface Cellular0/1/0, changed state to up
test-rtr#
test-rtr#ping 8.8.8.8 so c0/1/0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:
Packet sent with a source address of 10.176.162.135
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 49/87/200 ms
test-rtr#config t
Enter configuration commands, one per line. End with CNTL/Z.
test-rtr(config)#int c0/1/0
test-rtr(config-if)#vrf forwarding TRANSPORT
% Interface Cellular0/1/0 IPv4 disabled and address(es) removed due to disabling VRF TRANSPORT
PKF-test-rtr(config-if)#ip addres ne
PKF-test-rtr(config-if)#do sh run int c0/1/0
Building configuration...

Current configuration : 126 bytes
!
interface Cellular0/1/0
vrf forwarding TRANSPORT
ip address negotiated
dialer in-band
dialer-group 1
pulse-time 1
end

test-rtr(config-if)#do ping vrf TRANSPORT 8.8.8.8
% VRF TRANSPORT does not have a usable source address
test-rtr(config-if)#do ping vrf TRANSPORT 8.8.8.8 so c0/1/0
% VRF TRANSPORT does not have a usable source address
test-rtr(config-if)#
test-rtr(config-if)#

[Giuseppe Larosa]

Hello Perkin,

in some recent threads some colleague have reported the usage of dialer watch feature to trigger an LTE call.

There is also a VRF aware dialer watch feature see below

https://content.cisco.com/chapter.sjs?uri=/searchable/chapter/www.cisco.com/content/en/us/td/docs/ios/dial/configuration/guide/15-mt/dia_15_mt_book/dia_vrfaware_dia_watch.html.xml&searchurl=https%3A%2F%2Fsearch.cisco.com%2Fsearch%3Fquery%3DVRF%2520aw...

Dialer watch monitors the IP routing table if a monitored route is missing it triggers the call.

VRF aware Dialer watch monitors the specified VRF IP routing table.

see the last example using dialer interfaces that are mapped in VRF.

Edit:

the trick to force the call in the LTE example is to monitor a not existing route like 8.8.8.8 255.255.255.255.

The only doubt I have is if vrf forwarding <name>  and ip address negotiated are compatible on cell interface.

As an alternative you should be able to try to use a dialer interface linked to the cell interface.

Hope to help

Giuseppe

[perkin]

many thanks Giuseppe

I just read the link, although I still confusing those BRI interfaces and multiple types of configuration (my CCNP remote access was the lower mark I had in 10+ yrs ago...) also I am a bit confused with the chat-script configuration, since some post said LTE is not required chat-script (and actually it works for me)

anyway, I do a quick dialer watch-list,  but it is not VRF Aware

test-rtr(config)#dialer watch-list 1 ip 0.0.0.0 ?
A.B.C.D IP subnet mask

test-rtr(config)#dialer watch-list 1 ip 0.0.0.0 0.0.0.0 ?
<cr> <cr>

test-rtr#

This test router is ISR 4321 with 16.9.3 the latest ios-xe also I updated the firmware too.

[perkin]

update 2:

just tested and dialer-watch / group work with LTE reboot and not kick start the connection...

reviewed the link onc more time that mentioned this is IOS 15.5.M&T, seems I cannot found M or T in software.cisco.com under ISR

[perkin · Accepted solution]

Hello Giuseppe

how are you? just want to update this thread and let any know if they search

1) I found that on the NIM-4G-LTE-GA (at least this mode) NO any dialer map required

2) dialer watch will help to turn the interface up based on the route it checks on the same VRF (not 100% sure since I am just using something like 5.6.7.8/32),

3) dialer watch is not required "chat-script" only dialer watch-group and dialer watch-list will be ok

4) the problem I encounter before is not too consistent for me, after that I upgrade the firmware as well, and finally I realized we need to wait for 3+ mins after the router loaded before we can use dial watch to kick on the interface, (I suspected that 4G module is not fast enough like iphone :) )