[c-nsp] GRE tunnel optimization

[Adam Greene]

Hi,

I'm trying to pass IPSec VPN traffic over a simple GRE tunnel, with 
mixed results (some packet loss, high latency).

Configs on both ends:

==========
2811, 12.4(21), traffic is sent over bonded DSL lines
==========
interface Tunnel0
 ip address 172.16.16.9 255.255.255.252
 ip tcp adjust-mss 1460
 tunnel source x.x.x.x
 tunnel destination y.y.y.y
!
interface ATM0/0/0
 no ip address
 no ip mroute-cache
 no atm ilmi-keepalive
 dsl operating-mode auto
 hold-queue 224 in
 pvc 0/35
  protocol ppp Virtual-Template1
 !
interface ATM0/1/0
 no ip address
 no ip mroute-cache
 no atm ilmi-keepalive
 dsl operating-mode auto
 hold-queue 224 in
 pvc 0/35
  protocol ppp Virtual-Template1
 !
interface Virtual-Template1
 no ip address
 ppp multilink
 ppp multilink group 1
!
interface Multilink1
 ip address x.x.x.x z.z.z.z
 ip nat outside
 ip virtual-reassembly
 ppp multilink
 ppp multilink group 1

==========
1841, 12.4(24)T2, traffic is sent over Cablevision link
===========
interface Tunnel0
 ip address 172.16.16.10 255.255.255.252
 ip tcp adjust-mss 1460
 tunnel source y.y.y.y
 tunnel destination x.x.x.x
!
interface FastEthernet0/0/0
 description *** Cablevision ***
 ip address y.y.y.y z.z.z.z
 ip nat outside
 ip virtual-reassembly
 ip tcp adjust-mss 1460
 duplex auto
 speed auto

The VPN is being generated by Sonicwalls on both ends. I've set MTU to 
1460 on them as well.

I had originally set MTU to 1400, but it was worse.

Are there any obvious configurations I am missing to optimize this 
traffic?  For example, is  something like the following recommended on 
the Tunnel interfaces?

hold-queue 1024 in
hold-queue 1024 out


Thanks for your help.

Adam