SIP delay issue?

Hi! I have my system running perfectly.
I have Linksys SPA922 phones and running Asterisk 11.5.0

I’am experimenting voice delay like 1 or 2 seconds.
I don’t know why. We are here in the same office. So, I imagine is nothing about NAT issue.
We are here in the same building.

What you recommend me?

This is my phone configuration: Check the Bold lines

[quote]
[201]
type=friend
defaultuser=201
secret=9865978659
callgroup=1
pickupgroup=1
namedcallgroup=enterprise-group
namedpickupgroup=enterprise-group
directmedia=yes
directrtpsetup=yes

qualify=1000
dtmfmode=rfc2833
language=en
allowsubscribe=yes
subscribecontext=enterprise-hints
context=internal
subscribemwi=yes
disallow=all
allow=ulaw
allow=alaw
allow=g723
allow=gsm
allow=ilbc
allow=g729
mailbox=201@enterprise
callerid=“Phone 1” <201>
limitonpeer=yes
call-limit=300
transport=udp
callcounter=yes
busylevel=300
videosupport=yes
accountcode=201
tonezone=us
notifyringing=yes
notifyhold=yes
nat=auto_force_rport
host=dynamic[/quote]