The first thing I would do is determine whether or not you need to load share for outbound bandwidth. Typically an enterprise will have a lot more inbound traffic than outbound traffic, so if one of the circuits exceeds your outbound bandwidth needs by 30% or more, you may not need to load share across the multiple routers for outbound traffic. If this is the case, put all the routers in an HSRP group with the largest outbound pipe being active and the other 2 being standby to present one gateway to the firewall that is redundant across all of the routers.
If that is not the case, then you have to determine how you are going to load share. A layer 3 switch with multiple default gateways will work, but then you have to determine whether or not the load sharing will be per-packet or per-destination. You then also have to work out the issue of a circuit failure. If a provider circuit fails, and the router's Ethernet that is plugged into the switch is still up, the switch will still route traffic to that device because it has no way of knowing that the router has no available path to forward the traffic. If HSRP is not an option, and you need to load share to accommodate your outbound traffic, you should use a routing protocol such as OSPF to communicate between the routers and the switch. You redistribute the static default route on each of the routers into OSPF, if there is a circuit failure the router will stop injecting the default and the switch will stop routing traffic to it. Inbound bandwidth shouldn't be a problem, this will be taken care of by normal routing, inbound traffic to your network from each provider hits its respective router and the router sends it to your firewall/switch. I would answer these questions before trying to determine how the switch should be configured. -----Original Message----- From: kaushalender [mailto:[EMAIL PROTECTED] Sent: Monday, September 08, 2003 8:29 AM To: [EMAIL PROTECTED] Subject: vlan urgent [7:74955] Hi group, I will be glad if some one can help me on itI have a problem .We are planning to put firewall in our network.The problem is that firewall can point to a single gateway but i have multiple gateways for my network because we have taken bandwidth from different providers and all three bandwidth is terminated on different router's .Now they are Suggesting that we have to put a L3 switch in between firewall and all three routers and give one static ip address to L3 switch and than firewall will point that static ip .Can some one suggest how i have to configure cisco 3550 L3 series switch.Plz help Regards Kaushalender **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74965&t=74955 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
