Replacing 2801 (L3 Switch vs router)

[David Badolato]

I have a problem. We are currently using a SDWAN solution with an Advantech UTM (labeled SDWAN Active Core) device connected to a Cisco 2801 (see drawing below)

We are going to a HA SDWAN in which the Advantech device and the cisco 2801 will be replaced with Two Advantech's connected directly to the L3 Switch. see below.

My question is, can everything the router (cisco 2801) is doing be replicated on the switch so we can remove the router entirely? In other words, is it possible to perform the same routing the 2801 is now handling with the SG500 switch?

2801 route table:

Westside-2801#sho ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override

Gateway of last resort is 172.30.252.13 to network 0.0.0.0

S* 0.0.0.0/0 [1/0] via 172.30.252.13
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback1
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
C 10.40.2.0/24 is directly connected, FastEthernet0/0.1
L 10.40.2.20/32 is directly connected, FastEthernet0/0.1
C 10.40.10.0/24 is directly connected, FastEthernet0/0.2
L 10.40.10.1/32 is directly connected, FastEthernet0/0.2
C 10.140.0.0/24 is directly connected, FastEthernet0/0.3
L 10.140.0.1/32 is directly connected, FastEthernet0/0.3
172.30.0.0/16 is variably subnetted, 2 subnets, 2 masks
C 172.30.252.12/30 is directly connected, FastEthernet0/1
L 172.30.252.14/32 is directly connected, FastEthernet0/1

 

 

[balaji.bandi]

If the Router not doing any NATing - then you can replace with Layer 3 Switch ( or you can use exiting SG 550Switch - if that support the features) ( Hope you need DHCP on the switch, if Router having DHCP Server)

Not sure what kind of Bandwidth you have, but SG 550 able to handle. for testing, you can remove Csico Router and make changes and test it.

[Richard Burts]

The original post asks a pretty open ended question "My question is, can everything the router (cisco 2801) is doing be replicated on the switch" What is everything that the router is doing? The post only supplies very limited information about the routing that it is doing (seems to be pretty simple routing - locally connected subnets and a static default route). So from just a routing perspective it seems that the switch should certainly be able to replace the router.

 But are there other things that the router is doing? BB raises a valid possibility of NAT. Are there other functions (perhaps QOS, or PBR, zone based firewall, etc) that the router is doing?

[paul driver]

Hello
You need to elaborate on what services the router you are going to replace is currently providing, Switches usually dont have full L3 routing capabilites unless they are campus core size and above and looking at the feature set on this plaform of switche they do not.