Comware

Hi folks.

I'm checking my environment and during this checkup a question emerges. I know that HP 1910 48G has some layer 3 capabilities. I'm using this switch only with a layer 2 switch because I have a L3 SW on my environment.

If the responsibility to route between VLANs is attached to the L3 SW, and in all my L2 switches I have already defined a default gateway (L3 SW), what is the necessity to maintain an IPv4 route to default gw? An image is attached.

Thanks.

Maybe I'm wrong here...but if your LAN has a Layer 3 Appliance and this one (Firewall/Router) acts as Default Gateway for any connected VLAN you defined in your environment (I mean: VLANs connected using the same DG physical interface configured accordingly or VLANs connected using different physical interfaces physically separated, one interface for each seen single VLAN) then any Switch defined IPv4 route to any Default Gateway shouldn't be *so* mandatory for any client to reach its DG beacuse all (traffic flow), VLAN too, is ruled at Layer 2 level. Isn't it?

If your not using L3 functionality, you still need gateway set for reachability beyond the VLAN having IP address.

Examples are access to public NTP server, management from different subnets to name a few

The switch itself is a host on the network.

It needs a default route/default GW for the same reasons that any other host (eg a PC, server, or phone) might need one.

Definitely. That doesn't necessarily mean that the Switch needs to provide its Route to a DG to other hosts on the network it manages.

For its internal uses (NTP, DNS resolution, etc.) to have a Route defined to a DG is important (mandatory), I know that...but I thought the question was more related to why to provide it to other hosts in the Network (so "externally" to the Switch) where those hosts yet know how to (because are yet configured to) reach their DG.

Probably I misunderstood the question or the scenario.

What I want to say is whether the SW works only over the mac address layer, what is the point to insert a route using the network layer if the box does not understand IP address? I know that this switch model is a bit powerful than the default L2 switches but I don't want this box (1910) working with a power of L3.

All the Vlans and Vlans interfaces are on L3 switch as well as the IPv4 routes.
The hosts are pointed to DG.

Thanks in advance to everyone.

If you don't want this 1910 to act as a router.... don't  set default gateway on any host to the 1910 IP address. afaik, there's no command like "ip routing" like in the Cisco world to turn on/off routing capabilities

If you want the 1910 to be reachable beyond it's own subnet, you need to set a default gateway on it,  just like you need to on any IP device