Link Speed on switches/router

My question is regarding link speeds ...
On switch interfaces we have options of either 10/100/1000 Mbps.
FastEthernet Interface can have 10/100 Mbps and
GigabitEthernet Interface can have 1000 Mbps.
But the actual speed provided by Internet Service Provider is not this much, on T1 line it can have only 1.544 Mbps, so whats the use of having 10/100/100 Mbps ?
Routers are considered to be DCE devices which adjust their speeds according to the speed provided on line.
Service provider provides much less speed than configured on the switches and routers?
can anyone please help me in this concept ?

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networker050184

You can certainly have a 100 meg internet circuit if you pay the right amount of money. The service provider will sell you as much bandwidth as they can handle. Just means more money for them. You are also confusing a T1 with ethernet here, not the same thing.

You also have to think about traffic not being sent to the internet. If you have an internal server you are accessing wouldn't you want as much speed as possible? No point in limiting that connection to 1.5 Mbps because that is what your internet circuit is.

arsalan921

thanks networker for your reply, it has clarified my concept, now the servers which are internal will be accessed at the speed which has been configured on the switch. and the data from internet servers (such as yahoo's server or google server) will be accessed at a speed provided by service provider.

now for example if i have set up a network with 1 switch and a router, switch has got around 24 fastethernet ports and 2 gigaethernet ports , all the fastethernet ports are configured to be using 100 Mbps and all these have single PCs connected, ( 24 PCs connected to 24 interfaces ) and a switch connected to router over gigabit ethernet port. and then a router connected to a line provided by service provider. now if any one computer uses an internal server it will use 100 Mbps but how the speeds will change when using an internet ?

switch to pc = 100 Mbps configuration
switch to router = 1000 Mbps connection
router to service-provider = 1.544 Mbps.

peanutnoggin

arsalan921 wrote: »

thanks networker for your reply, it has clarified my concept, now the servers which are internal will be accessed at the speed which has been configured on the switch. and the data from internet servers (such as yahoo's server or google server) will be accessed at a speed provided by service provider.

now for example if i have set up a network with 1 switch and a router, switch has got around 24 fastethernet ports and 2 gigaethernet ports , all the fastethernet ports are configured to be using 100 Mbps and all these have single PCs connected, ( 24 PCs connected to 24 interfaces ) and a switch connected to router over gigabit ethernet port. and then a router connected to a line provided by service provider. now if any one computer uses an internal server it will use 100 Mbps but how the speeds will change when using an internet ?

switch to pc = 100 Mbps configuration
switch to router = 1000 Mbps connection
router to service-provider = 1.544 Mbps.

Arsalan921,

I don't think anything will change. You're switch is still going to "bottleneck" at 100Mbps. Because your switch is connected via GiG-E, that will not change the fact that it will pass the data to the clients at 100Mbps (which it is programmed for).

HTH,

V/r

~Peanut

Forsaken_GA

arsalan921 wrote: »

thanks networker for your reply, it has clarified my concept, now the servers which are internal will be accessed at the speed which has been configured on the switch. and the data from internet servers (such as yahoo's server or google server) will be accessed at a speed provided by service provider.

now for example if i have set up a network with 1 switch and a router, switch has got around 24 fastethernet ports and 2 gigaethernet ports , all the fastethernet ports are configured to be using 100 Mbps and all these have single PCs connected, ( 24 PCs connected to 24 interfaces ) and a switch connected to router over gigabit ethernet port. and then a router connected to a line provided by service provider. now if any one computer uses an internal server it will use 100 Mbps but how the speeds will change when using an internet ?

switch to pc = 100 Mbps configuration
switch to router = 1000 Mbps connection
router to service-provider = 1.544 Mbps.

If you only have a T1 for your internetwork connection, then your traffic is limited to T1 speeds. Pretty simple. You will probably want to deploy QoS, as it would be trivial for 24 computers to saturate the link.

In that setup, your gig links are better utilized as links to other switches to expand your port density.

In my setup, otoh.... I have 8 10 gig circuits, so those gig uplinks to my routers actually push some serious traffic

Kaminsky

Not every packet hitting the switch will be going to the router and not every packet going to the router will be going to the carrier circuit.

hypnotoad

It might seem pointless to have a gig connection to a router that only has a T1, but you could also configure your router to do router-on-a-stick. You could also have a caching module inside your router, or your router could handle your telephones, or something like that...in which case the router would make better use of the LAN speed.