[nsp] GigaBit Ethernet on a 7507

Burns, Keith Keith_Burns at icgcomm.com
Tue Nov 11 12:04:52 EST 2003

> -----Original Message-----
> From: Streiner, Justin [mailto:streiner at stargate.net]
> Sent: Tuesday, November 11, 2003 9:30 AM
> To: cisco-nsp at puck.nether.net
> Subject: Re: [nsp] GigaBit Ethernet on a 7507
> On Tue, 11 Nov 2003, Ernest Altbart wrote:
> > is installing a GEIP in a 7507 the only way to make that 
> router Gigabit
> > Ethernet capable ? If yes, does anyone have experience with it (I
> > presume yes) ? And if so where you encountering problems 
> with specific
> > IOS releases ?
> Yes, a GEIP/GEIP+ is needed to do gig-e on a 7500.  I don't how much
> throughput you can reasonably expect.  That depends on everything form
> what type of RSP you have to what version of IOS you're running.
> As far as I know the VIPs will not recognize the PA-GE.
> > And related to that: Does the GEIP support ZX (up to 130km) 
> GBICs ? And
> > has anyone experience with ZX GBICs over a distance of 20km ? (Is an
> > attentuator needed ?)
> According to the CCO, ZX GBICs are supported in a GEIP.  I've 
> never tried
> it myself, though.
> http://www.cisco.com/en/US/products/hw/modules/ps2033/products

!The ZX spec calls for a link power budget of 23 dB over 9 or 10mm
!single-mode fiber I believe.  20 km may provide enough attenuation to keep
!the ZX GBIC's receive optics from getting overloaded.  You should probably
!check the link power budget numbers for the fiber span you plan to light
!up beforehand.  If you have access to a fiber test set/OTDR, you can see
!where the splices and cross-connects are because you'll see some signal
!loss at each point.

Rough rule of thumb is 0.25dB/km for attenuation, but as Justin said, an
OTDR will give you the definitive fibre attenuation loss, and if you are
leasing the fibre, this information is a reasonable request to make of the
people you are leasing from.

The specs don't show the Rx sensitivity (which you will also need to
determine how much attenuation you will need) so you might want to contact
the TAC re: this one. Assuming -9dBm Rx sensitivity, and 0.25dB/km (giving
5dB attenuation over 20km), this leaves you with 18dB budget which will
probably mean you will need attenuation.

If you want to fudge with it without getting the info from Cisco, try a 10dB
attenuator first, then a 5dB (start high, work down, don't want to blind
anything ;-), using the attenuators on the Tx). 

Hope this helps.


Keith Burns
Principal Network Architect
ICG Telecommunications
IP Ph: 303-414-5385
Cell:   303-912-3777 

"The dogs may bark, but the caravan rolls on...."

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