[c-nsp] Catalyst4006 Vlan interface drop ping packet of 18000 byte

[Joe Shen]

Hi,

We use Catalyst4006 to provide L2 ethernet connection.
The topology is:


Server --- Cat4006(1) --- Cat6509 --- Cat4006(2) ---
Workstation

Both Server and workstation are Windows system.
Server's IP is 192.168.0.2, workstation's IP is
192.168.0.110, Vlan interface on Catalyst4006(1) has
IP address 192.168.0.144, Vlan interface on
Catalyst4006(2) has IP address 192.168.0.244. 

When we tried to ping 192.168.0.2 from workstation,
any packet ( 100 bytes to 30000 bytes) succeed; but,
when ping Vlan interface address on either
Catalyst4006 can only succeed with packet whose size
is less than 17000 bytes. Once packet size is larger
than 17000 byte, no ICMP_Echo_Response is received.

On the other hand, if we attach a
notebook(192.168.0.145) to fast ethernet interface on
cata4006 directly, 'ping' could succeed with packet
size 20000 bytes. 

Why? 

thanks in advance.

Joe 

_________________________________________________________
Do You Yahoo!?
注册世界一流品质的雅虎免费电邮
http://cn.rd.yahoo.com/mail_cn/tag/1g/*http://cn.mail.yahoo.com/