Since we have a tech topic I thought maybe we could have a networking one as well to separate the two issues and make it easier for people to get networking help.

So for the first topic of the thread I had a question about a switch. The switch I might be getting is a Cisco 3548 switch. I hav read this can manage VLANs but I couldn't find if it able to handle basic routing between them. I assume not due to the nature of VLANs but I can't afford the extra Cisco router for it. The switch is end of life as of years ago but it will be used mainly to learn from and hook a few personal servers and PCs up to, and the price is very low (under $100) so it wouldn't be too much of a loss. A 24 port version is only a couple dollars cheaper so to get the most out of my money I am looking at a 48 port.

Can anyone find a definate answer as to if the switch can route between the VLANs it makes, again I assume not. Even if not would it be worth the small investment to get familiar with it and possibly use it for bigger things in the future?

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I don't think you're likely to find many users of an managed switches on here, but hey, maybe I'll be surprised. Less likely to find someone using a specific switch...

Buying EOL stuff to get familiar with it makes no sense to me. It's possible Cisco changed some stuff, making what you learned much less useful. We are talking about something a decade old, half of which time has been after its EOL.

More crecent equipment is outside of my price range at this point and for what those switches do even if I want to use it in the future for something I am sure the capabilities will be fine. But there is still the debate if I really want to buy it or save the funds for something else since I don't actually plan to pursue my CCNA but to at least learn a little more networking.

Oh god. This is my least favorite of any kind of programming...Which kind of svcks because it's very useful.

Huh? Where's the programming?

I am working on my CCNA, taking a class for it. We work on Cisco 2960 switches and Cisco 1841 routers for the most part. We also use simulation software called Cisco Packet Tracer. (though I am unsure if thats available to anyone not enrolled on the Cisco Academy site) There should be open source simulations out there as well.



Its not really programming, more configuring. An example of one my running configs I have saved.

I am thinking I will look into HP switches since as DEFRON pointed out the Cisco I was considering is end of life as of years ago. One of the HP switches I found, the J3299A, seems to have an update as of November 2010. Another was last updated in 2009. Do you all feel like these might be better choices?

I'm sure you know this, but you can program such things as packet injections, which to my knowledge would fall under networking. I try to replicate a lot of things other programs do in my spare time, and creating connections, injecting packets and so on have always been incredibly tedious and dysfunctional. I'm probably just too much of a novice.

I can't seem to tell from the spec sheets for the following switches which is newest and might be best of the three. They are all HP and the mdel numbers are: J3299A, J4813A, J4868A. Does anyone have any information on them? I searched HP's website but didn't get too far with it for some reason, I know they are older but I should at least be able to find a manual or something. And the J3299A for some reason in it's manual it labels the ports as 10BaseT but then shortly later calls them 10/100BaseT ports so I am confused which it actually is.

That's not really the same thing, as said, it's more network configuration.

*wipes inch thick layer of dust off CCNA textbook*
Is the 3548 a layer 3 switch? if it is all you need to do is assign the right IP addresses to the VLAN interfaces and enable IP routing (don't know the command for that).

EDIT: I found a forum post on google saying that the switch is layer 3, but no official site.

I had found the same thing but I couldn't tell if it was a definate answer since Cisco stopped supporting the switch as of years ago. This is partly why I started to look at low cost HP switches. But the ones I found I can't find a good comparison of the specs or actual release dates for the equipment.

First of all, I know nothing about Cisco switches except some very basic things, very basic, so this is probably a silly post but if you want to map vlans wouldn't you need at least 2 switches? One for each LAN or at least one for a group of LANs?

It just seems to me that if you have one switch to represent multiple LANs and one switch, wouldn't it just be like one big LAN?

The VLANs would simply be, from my understanding, the equivalent of using multiple switches for each LAN but merged into one to become virtual. This makes them easier to manage and lowers the equipment cost overall by requiring 1 switch as opposed to multiple. VLANs are available on no-Cisco equipment as well but the switch I was originally looking into specifically stated it as a feature. The problem I was having is the VLANs are considered separate networks so there would need to be a router involved but the switch in question possible can handle those basic tasks on its own rather than needing the other equipment for the basic functionality. But it was never clear if it actually could do it or not.

Right so I guess my lack of knowledge here is just messing with my brain but isn't a router just operating on a different layer in the OSI stack? I thought switches and routers were pretty much the same thing. Is that not true?

I mean I'm not sure I understand the difference between a VLAN and a regular LAN. Let's take an example:
If I have LAN 1 connected to port 1 and that LAN has a number of virtualized hosts.
Then I have LAN 2 connected to port 2 and that LAN has a number of virtualized hosts.
Wouldn't the switch just send packets between port 1 and 2? If so, how would that be different than 2 physical LANs connected to ports 1 and 2.
They seem the same to me but perhaps I'm probably overlooking a lot of details.

Routers route traffic based on IP (layer 3) where switches use MAC addresses (layer 2).

I think I will be going for an HP ProCurve 2524 (J4813A) 24 port switch rather than the Cisco due to price but I am not completely decided yet/

Well, you do have layer-3 switches, which pretty much every fully-managed switch is. The main difference between a router and a layer-3 switch is the method of getting packets to their destination. For example, NAT and PAT are in the realm of routers alone (though you can get some very high-end layer-3 switches with it, but it's a feature not really suited for switches, or the hardware of switches). Pretty much anything related to WAN will be lacking from a layer-3 switch.

Layer-2 switches, as Dark mentions, will just use the data-link-layer (layer-2)

@Jethrol the point of VLANs are to offer the ability to elegantly network devices and divide it up without purchasing more expensive hardware. For example, I could VLAN my SIP from my wireless from my clients from my service computers from my printers. Now I can implement policies based on these VLANs rather than the individual devices and by extension more easily restrict communication between the groups.

So, where's CCNA when you need him?

This thread practically has his name on it

I actually have a question.. sorry for the double post..


what's the contemporary equivalent of an old school null modem cable?


A double headed USB cable?

Looks like I will be going with the HP ProCurve 2524 (J4813A) 24 port managed switch. I can create VLANs but not route between them which might not be an issue after all. If I wanted to just break the network up couldn't I just give it the default gateway of my home router and then the VLAN can get out but not talk to the other VLANs? For the moment when I introduce a wired router, I am currently stuck with wireless only, any small home router should let me connect to the WAN but not between VLANs correct?

Yeah, all VLANs should have access to uplink, and therefore be able to reach the router, and therefore WAN. Do note that any VLANs will also be able to access any other devices connected directly to the router. This can be changed by unassociating the switch port to all ports except WAN. This is not something most routers can do by default, but is power that can be obtained through OpenWRT/DD-WRT.

Well I don't mind if there is access to other devices on the router that isn't a big deal if it even works out thats how I set it up. I was just curious from a connectivity standpoint if that works.

Where I work we just use HP switches, bit cheaper than Cisco. We only have one office setup with VLAN though - we've got a VLAN for our VoIP system and 1 for everything else. It's handy because then we only needed to buy 2 switches, 1 for failover. They're PoE, so it saved us a pretty penny.

The VLAN itself was very easy to setup on the HP switches, can't remember the model though off the top of my head.

As far as I remember anything after series 3000 allows you to trunk between VLANs and across switches. Before that you will have to get another router to trunk them up. Perhaps you can google from here cause I'm not 100% sure.

I am going with the HP J4813A switch. It is half the ports but more current as far as I can see and HP has lifetime support on all devices, s the 3568 Cisco switch isn't even really mentioned anymore due to end of life. I don't even need all 48 ports anyway, the one disappointment with the HP is it doesn't route between VLANs natively so I would need a router but I don't have enough devices at this point for it to really make a huge difference. I am already stuck with exactly what configurations I could put on the switch for the amount of devices being connected. Good learning experience either way though.