Ch. 6 * (Backbone Distribution Systems) Flashcards
One level hierarchial star
Links all bldgs in a campus back to MC (CD)
MC should be at ___ of bldgs being served
Center
Physical ring
Not double ring
Physical ring
Disaster recovery (seldom recommended)
TR
Enclosed architectural space
TE
Case or housing
Most cost-effective transmission mediums
Fiber - data
Copper - voice
Ideally, the MC would be in the ___
ER (equipment room)
10Gbps @ 984’
OM3
Building backbone
22-24 AWG
Campus backbone
19-26 AWG
Maximum backbone length
2,625’
Vertically aligned TRs (stacked closets) advantages:
Accessible backbone cable sheaths
Distributing circuits
Slots
1” high curb
Sleeves
1” above floor
5 sq’ of slots serves ___
40,000 sq’ of floor space
Supporting strands
Heavy backbone cables
Supporting strands extend from ___ to ___
Highest floor, basement
Insert cable ties every ___ of the strand
1 meter
Indoor hardware is ___ varied than outdoor hardware
More
Tight buffered
900 µm (indoor)
Loose tube
250 µm (outdoor)
Non conductive fiber backbone bend radius
10 X under no load
15 X when being pulled
Conductive fiber backbone bend radius
10 X under no load
20 X when being pulled
Pre-connectorized patch cords
Fast
Cost isn’t the concern
Fiber pigtail cable
Factory connectorized on one end
Unterminated on the other end
Double star topology
Hierarchial
Backbone star topology
No more than 2 cross connects
Connections between any two HCs
No more than 3 cross connects
Multimode fiber is more common due to ___
Cost-effective transceivers
Most common application for fiber
Multiplexing
At least ___ cable ties should be used per floor on support strands
3
Steel strands
.25”
Open shafts
Okay
Elevator shafts
Avoid
Qty of 4” sleeves per bldg
4
add 1 if over 40,000 sq’
OS2 length @ 10 Gbps
32,800’
Depth of backbone slots
6” - 24”
OS1 length @ 10 Gbps
6560’
What type of fiber is rated for 1 Gbps at 984’?
OM2
Second level Crossconnect is between ___ & ___
HC & IC
Fiber strength member
Aramid yarn
Fiberglass rod
Steel rod
Type of link from MC to IC
Can be either:
- interbuilding
- intrabuilding
OM2 length @ 1 Gbps
984’
First level crossconnect
Between MC & IC
Used to secure large, heavy backbone cables
Toggle bolts
Masonry
Straps
Two key parameters when selecting fiber electronics
Attenuation and bandwidth
Direct connections between TRs
Allowed if ring/bus