I could see that T656 was already created, as a result of https://forum.vyos.io/t/inconsistency-in-wirelessmodem-wlm-interface-behavior-could-be-bug/1492.

However, T656 also wanted to fix a few other items. Perhaps, we can just fix the interface naming issue alone as part of this issue, and use T656 for other issues. The fix proposed by Subbu will make pppd to create the interface with wlm0 in the very first attempt, rather than the existing model of having pppd create the interface as ppp0 and then use the 0003_rename-wirelessmodem to change the name, thereby leaving pppd in an inconsistent state

nuviso@ubuntu:~/vyos/build-iso/pkgs/vyatta-wirelessmodem$ cat 0001-T701-LTE-interface-dosen-t-come-up.patch
From 00a04474535ec0eb2b17fe1d4368abff7f3aae46 Mon Sep 17 00:00:00 2001
From: Subramonia Pillai <[email protected]>
Date: Wed, 20 Jun 2018 10:57:53 +0530
Subject: [PATCH] T701: LTE interface dosen't come up

templates-cfg/interfaces/wirelessmodem/node.def | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/templates-cfg/interfaces/wirelessmodem/node.def b/templates-cfg/interfaces/wirelessmodem/node.def
index 69d44fc..f185b93 100644

• a/templates-cfg/interfaces/wirelessmodem/node.def

+++ b/templates-cfg/interfaces/wirelessmodem/node.def
@@ -60,7 +60,7 @@ end: if [ -f /var/run/ppp-$VAR(@).pid ]; then

echo -e "lcp-echo-failure 0\n115200" >> $tmpfile;
echo -e "debug\nnodefaultroute\nipcp-max-failure 4" >> $tmpfile;
echo -e "ipcp-accept-local\nipcp-accept-remote\nnoauth\ncrtscts" >> $tmpfile;

• echo -e "lock\npersist\nlinkname $linkname" >> $tmpfile;

+ echo -e "lock\npersist\nlinkname $linkname\nifname $linkname" >> $tmpfile;

if [ -n "$VAR(./network/@)" ]; then
  network=$VAR(./network/@);

1.9.1

Forum says issue is fixed. Also WWAN underwent a major rewrite - should be all good now.