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New Member

Do I need a new router?

We currently have an ASA 5505, an 1841 router-on-a-stick, and all gigabit switches.  The ASA inside interface is on the LAN and the 1841 is of course on the LAN.

I am looking to add VoIP to my LAN and am thinking that I need a new router.  A 1941 or 1921 is what I am thinking.  My question is (as above) do I need a new router?  I think yes becuase the 1841 is only 100Mbit.  Is that correct thinking?  How much does it matter in this situation?

This may require a seperate thread, but my ASA is coming up on 5 years old.  Should I look at consolidating these roles?

Thanks.

12 REPLIES
VIP Purple

Do I need a new router?

Are you using the 1841 for inter-vlan-routing? That's not really clear from your posting. If yes, then better use a layer3-switch for that. That's what L3-switches are for and they give you all the speed you need.

For the ASA: A firewall should not be shared with an internal code device. Are you worried that the ASA could break in the near feature? Then you should ask your cisco partner for a smartnet. If you in addition to that need more features (perhaps your ASA is also too old to upgrade to an up-to-date software), then you could look into the ASA5512-X (again with a SmartNet service).

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New Member

Do I need a new router?

I have SmartNets on everything and am currently not doing any VLAN routing at all.  I'm most concerend about bandwidth since I have gigabit everything but the 1841 is only 100Mbit.  Do I need/want a gigabit router in this situation, or is the 1841 sufficient?

Re: Do I need a new router?

If it were me, I would get a 2900 series router.

Look at the pps, and make sure it works for your enviornment. Also, understand that the more features you turn on, the more CPU cycles, are taken away from forwarding traffic etc.

Now just to be sure, you do you 100Mbps ISP Link?

      

The above posted has a very good point. If you have other switches, would it be possible to turn 'ip routing' on those switches, and terminate your VLANs from there? Then you could have a default route to the ASA?

New Member

Do I need a new router?

I'm talking LAN routing, not WAN routing, so no, I do not have 100Mbps from ISP.  I will have VoIP on LAN only.

Right now, the 1841 i the default gateway for the LAN and the 0.0.0.0 0.0.0.0 route is to the ASA.

VIP Purple

Do I need a new router?

ok, in fact that is what is normally calles inter-vlan-routing ... ;-) The best solution would be to use a layer3-switch in this situation. That could be a 3560 compact-switch or even a SG300-10 could be a viable solution there.

The 1841 can route about 38 MBit/s. If your Internet-usage is below that, the 1841 could be enough. Just look at the cpu-rate at times of high internet-usage. If you have more internet bandwidth, you should change the router against something fast (switch or router).

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VIP Purple

Do I need a new router?

If it is not inter-VLAN-routing, what are you doing with the router? Just wondering because a router-on-a stick is nearly always used for that purpose.

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New Member

Do I need a new router?

The router is the default gateway on the LAN.  Previously we had a point-to-point T1 that went down a lot and used this router to fail the route over to a site-to-site VPN.  We no longer have the remote office, so I took that route out and now the 1841 is just the default gateway on the LAN.

Maybe I no longer need the router, and the ASA would be sifficient?

VIP Purple

Do I need a new router?

Having the ASA as the default-gateway for the clients is a bad network-design in most situations. Only if there will never be a second exit to the network with a different device, then it could be a valid solution.

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New Member

Do I need a new router?

Right.  So, even thoguh my /24 network is not very complicated, it's still good practice to have a router AND a firewall instead of JUST a firewall.

So, should I upgrade to a 1921 or 1941 when I add VoIP to my LAN, or is the 1841 still sufficient?  That's really what I'm trying to figure out.

LAN = 1000Mbit

1841 = 100Mbit

^^ That is the meat of my concern.  Will I gain anything by replacing the 1841?

VIP Purple

Do I need a new router?

Probably you won't get much benefit from a bigger router. The traffic that leaves the voice vlan is normally not that much. If the router can handle the actual traffic it will also handle the additional traffic when you deploy VoIP.

I still don't understand why you are only talking about an upgrade to 1921/1941 for your environment. Routers are used if you need additional services on top of ip-routing or if you want to use dedicated WAN-interfaces.

BTW, the 1941 can route up to about 150 MBit/s. So, only because the 1900 routers have Gigabit-interfaces doesn't mean the routers can handle gigabit traffic.

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New Member

Do I need a new router?

karsten.iwen wrote:

Routers are used if you need additional services on top of ip-routing or if you want to use dedicated WAN-interfaces.

Ok, I think I'm catching on here.  Are you implying that I likely do not need a router at all?  We needed it previously because we had multiple routes possible.  Now we only have a single route possible, so I am using a rotuer needlessly?

VIP Purple

Do I need a new router?

In general, a layer3 switch is a router. But one that has more preformance and less features then a traditional router. It's not about the amount of routes, that's more dependent on the platform. It is that you can connect WAN-interfaces like DSL. You can build VPNs, activate firewalls do NAT and really flexible QoS. Thats most of the time not possible with a Layer3-switch. But a L3-switch for the price of a 1941 gives you routed gigabit-performance on all interfaces which is much more then traditional router could handle. From the routing-perspective it's no different then a router with many interfaces.

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Don't stop after you've improved your network! Improve the world by lending money to the working poor:
http://www.kiva.org/invitedby/karsteni


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Don't stop after you've improved your network! Improve the world by lending money to the working poor: http://www.kiva.org/invitedby/karsteni
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