cisco router question

[Meractik]

out of all the fast mediums that could be used (firewire, usb 2.0 etc...) why do CISCO routers use a serial interface when connecting DCE -> DTE ??

 

[nick128]

legacy? MOre than likely its that. it's not like it's a high bandwidth application, and while RS-232 and DB connectors ain't the greatest, they get teh job done.

 

[Aves]

Firewire and USB are serial interfaces. Even it is possible to change, why would you want to make your stuff incompatible with other perfectly good equipment.

 

[Meractik]

i was just thinking that since the data has to travel through the connection on serial it might be more beneficial and less of a bottleneck if it was updated from the RS-232 serial connection....it could be done slowly so that each device is eventually up to par with the speed.

My reasoning for this thinking was that with networks now in the Gigabit realm and moving into 10Gb and TB etc.. it would be beneficial to make the connection more capapble of pushing more faster, instead of just improving the DCE encoding of data to make it easier to push...

 

[ScottMac]

Because then you can connect all of your equipment up with a Terminal server for remote console connections.

If they exist at all, USB or Firewire terminal servers are pretty scarce.

Next, why do you need something that fast?
9600 (optional: up to 115K baud) baud is just fine. It wouldn't be worth it for the extremely rare times when an XMODEM IOS transfer is needed.

RS232 fits the bill quite nicely.

FWIW

Scott

 

[Aves]

Originally posted by: Meractik
My reasoning for this thinking was that with networks now in the Gigabit realm and moving into 10Gb and TB etc.. it would be beneficial to make the connection more capapble of pushing more faster, instead of just improving the DCE encoding of data to make it easier to push...

Well the serial interfaces on routers are for WAN connections which are still mostly T1 speed (1.5Mbps) or less.

 

[Meractik]

alright well at least now i can classify the existance for just using serial, thanks alot for the info everyone. 🙂

 

[spidey07]

Originally posted by: Meractik
out of all the fast mediums that could be used (firewire, usb 2.0 etc...) why do CISCO routers use a serial interface when connecting DCE -> DTE ??

To maintain complete compatability across all platforms.

and by very definition DCE/DTE are serial. Almost all wan connections are serial based up untill you get into direct fiber. That is the very foundation of networking.

 

[nweaver]

The serial ports on cisco routers (wan links) are capable of much faster then t1 speeds. Serial can be fast...USB is serial, remember. Think of them as "Cisco USFireware 1.0" if it appeases your ego. 🙂

 

[Aves]

Originally posted by: nweaver
The serial ports on cisco routers (wan links) are capable of much faster then t1 speeds. Serial can be fast...USB is serial, remember. Think of them as "Cisco USFireware 1.0" if it appeases your ego. 🙂

I'm assuming the OP was referring to regular synchronous serial interfaces which I believe have a max supported speed of ~2Mb/s. I could be wrong.

 

[spidey07]

Originally posted by: aves2k

Originally posted by: nweaver
The serial ports on cisco routers (wan links) are capable of much faster then t1 speeds. Serial can be fast...USB is serial, remember. Think of them as "Cisco USFireware 1.0" if it appeases your ego. 🙂

I'm assuming the OP was referring to regular synchronous serial interfaces which I believe have a max supported speed of ~2Mb/s. I could be wrong.

yep, you could go high speed serial interface HSSI for 45 Mbs.

Thing is with USB, et all is they are short distance applications and don't have the leads or protocol to really do serial (DTR, DSR, DCD, etc) or high reliablity network communication.

 

[Meractik]

so serial RS-232 is also beneficial to use b/c it can sustain better data integrety over longer periods of time then usb/firewire..?

 

[spidey07]

Originally posted by: Meractik
so serial RS-232 is also beneficial to use b/c it can sustain better data integrety over longer periods of time then usb/firewire..?

for low bandwidth applications 232 is tried and true.