Question about Cisco serial interfaces

[ramirez]

What's the difference between these two (besides physical connector)? Is the HSSI considered legacy?

 

[BornStar]

HSSI requires an external CSU/DSU for the T1. The CSU/DSU WIC has the CSU/DSU contained on the card so there is no need for an external unit.

This brings up an interesting question. What is the preferred method for using a CSU/DSU? Should one use an external or internal unit?

 

[ramirez]

Also, which is the preffered method for a lab? Considering it's going to be 2 of them back to back.

 

[jlazzaro]

we use externals mostly because verizon provides us with one for every circuit.

if we had to buy them seperate not sure which id buy...prolly still the external. while its less cabling, rack space, and power to have them on the card, i still like the idea of have the csu/dsu seperate for troubleshooting purposes.

 

[ramirez]

Originally posted by: jlazzaro
we use externals mostly because verizon provides us with one for every circuit.

if we had to buy them seperate not sure which id buy...prolly still the external. while its less cabling, rack space, and power to have them on the card, i still like the idea of have the csu/dsu seperate for troubleshooting purposes.

What kind of cable do you use to interface the CSU/DSU (530, 449)?

 

[azev]

HSSI offers higher speed than regular speed than regular T1/CSU/DSU.
But like everyone here said, it still requires CSU/DSU

 

[cmetz]

ramirez, HSSI is typically seen going to DS3. V.35 is typically seen going to a T1 CSU. Both are not typically seen in new installations because routers have line cards with built-in CSUs these days.

For T1s, basically always use the integrated T1 CSU WIC.
For DS3s, basically always use the DS3 card with the CSU built in.

 

[Pheran]

Originally posted by: jlazzaroif we had to buy them seperate not sure which id buy...prolly still the external. while its less cabling, rack space, and power to have them on the card, i still like the idea of have the csu/dsu seperate for troubleshooting purposes.

Yuck, I hate external CSU/DSUs. They waste space, are often in some stupid form factor that isn't rack mountable, and usually have some obtuse interface for diagnostics. I'll take an integrated CSU/DSU on a Cisco router any day - you can easily loop it from the IOS CLI and you get rid of a bunch of cumbersome hardware/cabling.