General Networking/Lan/Wan/Cisco time delay issue


QUESTION: Dear Sudhanshue

I have a network with 3 cisco catalyst  3500.  When I move my computer from one of cisco  ethernet ports      to another ethernet  port of the same cisco or from one cisco switch to another cisco switch. I have to wait for a long period,  For example 10 mins,  to be able to connect to  internet.
Is there any configuration of Cisco that needs to be modified to reduced this time delay.


ANSWER: Hey Andre...
Certainly there are configurations which can help you fasten it up. However, apart from changing parameters on the switch you may need to look at name resolution as well. Do you use any name services  i.e. DNS. If yes, Is the server local? or if not you may want to have a local DNS server and should look for a caching server as well. Of course you need to look at the cost benefits depending upon the business you are in.

Do you get any error message while switch is trying to connect? Please share them with me.

In the mean time do following on the switches:
1. Enable portfast  on the ports where you are sure to connect your PCs. Do not do this if there is any port which connects to another switch.
Switch#configure terminal
Switch(config)#interface fastethernet 0/10 (assuming this has PC connected)
Switch(config-if)#spanning-tree portfast
Switch#copy run start

2. On the same port disable DTP - "switch  port mode access"
3. Keep Speed and Duplex both on Auto at the switch side.

this should help and let me know in case you get stuck.

---------- FOLLOW-UP ----------

QUESTION: Thanks Sudhanshu

Could there be a MAC ADDRESS table aging time, also causing this issue?


Sorry for the delayed reply, Andre, as I was travelling for last whole month and could no catch up with mails and other stuff like this. Were you able t resolve the issue. Possibility of aging MAc table is always there. You can try flushing it.

General Networking/Lan/Wan

All Answers

Answers by Expert:

Ask Experts


Sudhanshu Gupta


Any question related to IP routing protocols - BGP/OSPF/IGRP/EIGRP/RIP, HSRP. Bridging/DLSW, Cisco routers and Switches, LAN/WAN installation and monitoring.


I have about 14 yeras of experience in networking. I am an MCSE and CCIE (7334).

©2017 All rights reserved.