Archive for LAN Switching
UDLD and EtherChannel Configuration
Posted by: | CommentsA data centre network for a client I work with had an interesting issue this week. For no apparent reason some users within the data centre environment reported connection issues to hosts in the network. They were able to connect to some hosts but not others. Then all of a sudden connection would be restored but quickly lost again.
One of my colleagues was able to access two of the core data centre switches but I could only get to one. A very quick trip to the data centre floor and a console cable connection into the core data centre switches revealed the issue. Read More→
Popularity: 91% [?]
OSPF Passive Interface Command
Posted by: | CommentsI was recently asked by a client to help troubleshoot an issue they were having after upgrading the IOS on two of their core Cisco Catalyst 6509s. The two switches are connected together by three 1Gb fibre links that run about 500m between two buildings (Building A and B). Two of the links are bundled together in an 802.1q Etherchannel. Only one vlan, 100, is allowed to cross the link and this vlan is used purely for traffic to and from a cluster of Call Manager 4 servers. The other link is a 1Gb layer 3 fibre link that is used for any other user traffic across the core switches.
Here is a high-level layout of the switches and their connections. All IP addresses and vlans have been changed from their original values.
Network Layout
The 6509s also have links to other core switches within the network, so if the layer 3 link goes down traffic should be routed through these other switches. Read More→
Popularity: 67% [?]