[c-nsp] VLAN subinterfaces on 7609 Router

[Wes Decker]

Hi all,
  It appears that the 7609 Router is somehow blocking
VLAN frames in one direction. Here is my equipment config:

                         g6/1.2                  swap VID  VLAN       VLAN
Agilent    VLAN 4      CISCO   VLAN 2  GbE        (2 to 3)    3  GbE     
3  Agilent
Router   <-----------> 7609    <-----> Port <---> [switch] <---> Port 
<----> Router
Tester     192.7.1.x   Router           0                          
1         Tester
Port 0               g6/3.4    |                                        
    |Port 1
192.7.1.1                      |<--------------- 192.11.1.x 
--------------->|192.11
VID 
4                                                                        
.1.1
                                                                            
VID 3

CISCO 7609 Router has Gigabit Interfaces configured as follows:

interface GigabitEthernet6/1
no ip address
logging event link-status
!
interface GigabitEthernet6/1.2
encapsulation dot1Q 2
ip address 192.11.1.254 255.255.255.0
!
interface GigabitEthernet6/3
no ip address
logging event link-status
!
interface GigabitEthernet6/3.4
encapsulation dot1Q 4
ip address 192.7.1.254 255.255.255.0
!

Other 7609 config info:

Current configuration : 4752 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
service counters max age 10
!
hostname FW-7600
!
no aaa new-model
vtp mode transparent
ip subnet-zero
!
mls ip multicast flow-stat-timer 9
no mls flow ip
no mls flow ipv6
mls cef error action freeze
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
diagnostic cns publish cisco.cns.device.diag_results
diagnostic cns subscribe cisco.cns.device.diag_commands
!        redundancy
mode sso
main-cpu
 auto-sync running-config
!        vlan internal allocation policy ascending
vlan access-log ratelimit 2000
!
interface Vlan1
no ip address
shutdown
!
ip classless
no ip route static inter-vrf
no ip http server
!
access-list compiled
no cdp run
!
control-plane
!
line con 0
exec-timeout 60 0
line vty 0 4
no login
!
end
----------------------------------------

The [switch] is inhouse equipemnt but basically
all it is doing in this case is swapping the
VLAN ID from 2 to 3 (and recalc of FCS) on frames.

So the basic connection under test is:
192.7.1.1 VID 4 <------> 192.11.1.1 VID 3
where 192.7.1.1  VID 4 is Agilent Router Tester(RT) Port 0
and   192.11.1.1 VID 3 is Agilent Router Tester(RT) Port 1

With everyting configured as indicated above,
test traffic passes cleanly from RT port 0 to RT port 1.

However, traffic from RT port 1 to RT port 0 is being lost
at the 7609 Gigbit 6/1 port (actually g6/1.2 subinterface).

IT seems strange that the 7609 can handle the traffic from
VLAN 4 to VLAN 2 without a problem but cannot handle the
packets from VLAN 2 to VLAN 4.

The frames are being sent from the GbE 0 port towards
port 7609 G6/1(.2) port....but G6/1(.2) port never increments
its INput frame counter.

Any ideas or suggestions as to why this is happening or
possible things to try would be greatly appreciated!

Another bit of info:  I can generate PINGs and get replies
in both directions and ARP requests to the &609 from both
RT #0 and RT #1 work ok.


Also please note, if I just connect the RT Port 0 as it is
but connect RT Port 1 directly to the 7609 g6/1.2 port and
set RT #1 to use VLAN 2 then traffic passes in both
direction cleanly between the two RTs.
           g6/3.4
RT #0 <------> 7609 <-------> RT #1
VID 4             g6/1.2      VID 2
192.7.1.1                     192.11.1.1

Similarly, if I take the 7609 out of the path
and just have RT #0 connected to RT #1 through
our GbE ports and inhouse [switch],  again traffic
passes cleanly in both directions between RT# 0 and RT #1.

RT #0 <------>  GbE Port 0 <---> [switch] <----> GbE Port 1  <-----> RT #1
192.7.1.1     VID 2                                        VID 3     
192.11.1.1
VID 2                          swap VID 2 & 3                        VID 3


I captured the packets flowing in each direction for the
previous two configurations and I see no difference in the
IPv4 packets/frames other than the VID as expected.
I will put a LAN monitor/sniffer on the GbE Port 0 to 7609 G6/1(.2)
interface for the 1st config above to see if there is anything
unique with these VLAN 2 packets between these ports (todays task!).

I have not created any static routes....the 7609 is just using
the "connected" subnetworks.

I have tried to use the CISCO configuration documentation but
it is kinda sparse on the configuring of "subinterfaces".

If there is additional info from the 7609 that I can provide,
please just let me know CLI commands to enter.

Thanks ahead of time for any replies!

Wes Decker
(wdecker at tellabs.com)
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