Hello everyone,
Today I will share with you how to deal with SIP trunk cannot change back after the GRE tunnel switchover on AR1200.
Between AR1220C and AR1220E, connect to ISP and reach each other. GRE over IPSec also is set up between the two devices. When the GRE tunnel is ok, the SIP voice traffic will go through the GRE tunnel. If the GRE tunnel down, the SIP voice traffic will go out with NAT and reach to each other. The issue is that, when GRE tunnel down, the SIP voice switch to NAT. But when the GRE tunnel recovery, the SIP voice traffic cannot switch back to the GRE tunnel.
Configuration on AR1220C:
#
interface Dialer1
link-protocol ppp
ppp chap user xxx
ppp chap password xxx
mtu 1492
ip address ppp-negotiate
dialer user gardppp
dialer bundle 1
nat outbound 2999
zone WAN
ntp-service in-interface disable
#
#
interface Tunnel0/0/3
ip address 10.255.0.25 255.255.255.252
tunnel-protocol gre
keepalive
source x.x.x.x
destination x.x.x.x
tunnel route-via Dialer1 mandatory
zone LAN
#
1. When the GRE tunnel is up, the VOIP traffic goes through the GRE tunnel. It means that the routing to each other is right.
2. When the GRE tunnel is down, the VOIP traffic goes out with NAT and reach each other. It means that the path switchover is ok.
3. When the GRE tunnel up again, the routing to the peer site can learn through the GRE tunnel. At that time, the nat session table still active. As the nat session table has a higher priority than the routing table, so the voice traffic still goes through NAT.
4. When customers reset the NAT session, the current session will be reset. There is no nat session table, the traffic will check the routing table again, the traffic will go through the GRE tunnel again.
The nat session table has a higher priority than the routing table, so the voice traffic still goes through NAT. When customers reset the NAT session, the current session will be reset. There is no nat session table, the traffic will check the routing table again, the traffic will go through the GRE tunnel again.
That is all I want to share with you! Thank you!