03-09-2009 06:45 AM - edited 03-06-2019 04:28 AM
I'm proposing the following layer 3 LAN topology. All connection link will be point to point routed ports (L3). EIGRP routing will run between all LAN switches using a /30 subnet mask.
The problem is the customer want to dual home all servers (AD & IPT servers) to the two core switches over VLAN 60 (6509-1 & 6509-2). Should I use a layer 2 link to carry HSRP traffic between the two switches. (please see diagram).
Will this cause problems with Eigrp routing. Please advise on network design.
03-09-2009 06:51 AM
Hello Colm,
yes you need a l2 link to carry the shared vlan
the servers need to use an active/standby strategy because they connect to two different switches.
note: this in part violates the hierarchical network design you should connect the servers to theh server farm functional block however this is possible.
EIGRP will not be a problem it will advertise the shared vlan/subnet to the core.
Traffic coming from the core can also need to go through the interswitch link.
Hope to help
Giuseppe
03-09-2009 06:51 AM
Colm
If you want to connect servers to the core switches and run HSRP then you will have to have a L2 link between the 2 core switches. Ideally you would have your servers connected to 2 access-layer switches which are then uplinked with L3 but i appreciate there is an additional cost to that.
So yes you need a L2 link either an access link in the server vlan or a trunk if there are multiple server vlans.
It won't affect the routing but i would
1) make the vlan interfaces passive under eigrp then no neighborships will be formed over the L2 link ie.
router eigrp 1
passive-interface vlan20
where vlan 20 is the server vlan.
2) If it is a trunk link you will need to
a) only allow the relevant vlans across it
b) make passive all the vlan interfaces for vlans that are allowed on the trunk
Jon
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