Chp 4 Backbone Distribution Systems Flashcards
MC is
Main Cross Connect. Campus Distribution
The cross-connect normally located in the (main) equipment room for
cross-connection and interconnection of entrance cables, first level
backbone cables, and equipment cables. Campus distributor is the
international equivalent term for main cross-connect
HC is
Horizontal cross connect. Floor distribution (for floor)
A group of connectors (e.g., patch panel, punch-down block) that
allow equipment and backbone cabling to be cross-connected or
interconnected with patch cords or jumpers to horizontal cabling.
Floor distributor is the international equivalent term for horizontal
cross-connect.
TR
Telecom room. TE is located here and is where HC is located
Backbone distribution components
Cabling pathways
ERs with (HCs, ICs, and/or MCs)
TRs with HCs
TEs with HCs
An EF
Transmission media
Misc. support facilities
IC is
Intermediate Cross connect. Building distribution.
The connection point between a backbone cable that extends from
the MC (CD [first level backbone]) and the backbone cable from the
HC (FD [second level backbone]). Building distributor is the
international equivalent term for intermediate cross-connect.
Conduit pathways
Shafts, conduits, raceways, tray, floor penetrations (e.g., sleeves or
slots), maintenance holes, hand holes, conduit banks (and other
outside plant pathways) that provide routing space for cables.
Equipment room
An environmentally controlled centralized space for
telecommunications equipment that usually houses a main or
intermediate cross-connect. (TIA)
Telecommunications room
An enclosed architectural space for housing telecommunications
equipment, cable terminations, and cross-connect cabling. (TIA)
TE
A case or housing that may contain telecommunications equipment,
cable terminations, or horizontal cross-connect cabling. (TIA)
Entrance Facility
An entrance to a building for both public and private network service
cables (including wireless), including the entrance point of the
building and continuing to the entrance room or space. (TIA
Backbone distribution system provides:
A backbone distribution system typically provides:
* Building connections between floors in multi-story buildings.
* Campus connections in multi-building environments.
Backbone distribution system is
the part of the property distribution system that connects various telecom spaces
Transmission media
The actual medium carrying the backbone signal:
Fiber Optics
Balanced Pair Cabling
Coax
Wireless
And termination hardware/connectors:
Cross Connects
Patch Panels
Patch Cords
Interconnections
Connector blocks
Note: backbone media may also be made of wireless connections
Miscellaneous Support
Materials needed for the proper termination and facilities installation
of the backbone cables.
These include:
* Cable support hardware.
* Firestop (see Chapter 7: Firestop Systems).
* Bonding hardware (see Chapter 8: Bonding and Grounding
[Earthing]).
* Protection and security.
Fundamental Cabling Topologies
Star
Bus
Ring
Hybrid Topologies
Hierarchial Star
Star-wired ring
Clustered Star
Tree and branch
Mesh
Redundancy Types
Active redundancy equipment utilizing redundancy pairs
Physical diverse cable routing
network equipment Redundancy uses
Redundancy pairs
Disconnect events:
cable breakage
significant loss on primary and redundant pairs
Patch cable/block removal
Disconnection of adaptors on cabling system side
Redunant pairs doesnt protect against
disconnect events
Redunant pairs doesnt protect against
disconnect events
Ring Topology general requirement
RECCOMMENDED a direct connection to the MC
Ring topology may be used when
-Existing pathways support it.
-Primary system purpose is fiber optic distributed data interface, SONET, or reverse ethernet
-There is a redunant path
Physical ring/logical star + Physical Ring network topology requires
knowledge of present and future telecom requirements to design this type.
see figure 4.5
Physical star/logical ring
Pathways are star topology, but the signaling will be routed in a logical ring
Physical star/logical ring applications
-a segment of the cabling will utilize existing cable
-the designer determines it is not possible to form a physical ring
Clustered star
Either physical star/logical ring or star topology from MC to nodes, and nodes with star topolgy.
Allows for fault tolerant routing at nodes
Bus topology
Linear connection. Only ideal if pathway is secure, traffic is not critical, and redundancy not required
Factors in Fiber Optic/Telephony/Data topology selected
Budget
Survivability plans
Redundancy requirements
Network traffic importance (critical or not)
Pathway infrastructure
Equipment functionality
Existing components to be reused
Tree and branch application
CATV, balanced pair, and Fiber Optic
Used to describe the MC node having cabling systems extending from them with multiple branches, along which splice points enable a single branch to serve multiple sub-nodes
CATV feeder/trunk cable
Coaxial cable from head end to branch
Factors in CATV topology selected
Signal loss characteristics of coax cable
Geographical area being served
Telephony/Data network
feeder/trunk
the MC cable
Fully Connected Mesh
all nodes connected directly to all other nodes w/ PTP link
Mesh benefit
high redundancy
Mesh setback
high cost
Mesh applications
Enterprise networks and Service providers routers
Partial Connected
some nodes are connected to more than 1 node with a PTP link.
Advantage: use redundancy similar to full connected with the major expenses
Partial Connected Mesh networks require equipment to have some sort of __________ to determine the routing path to use
logical routing protocol
PON
fiber - point to multi-point
used to be more cost effect than PTP by having unpowered splitters allowing a single fiber to server 32-128 premesis
can be FTTH, FTTB, FTTC
FTTC
fiber to the curb
FTTB
fiber to the building
FTTH
fiber to the home
1000BASE-X extended temperature range
-4.4 C to 85 C
-40F to 185F
Cost factors of fiber deployment
Singlemode/multimode
strand count
ONT
optical network termination
OLT
Optical line termination
Single mode fiber ITU-T reccommendation
Series G used for subscriber access in support of SDH and SONET
Balanced Twisted Pair PTP rates/names/term
10Mb/s and 2Mb/s, 10PASS-T and 2PASS-t, EoDSL
Balanced Twisted Pair PTP applications
MDU premesis, neighborhoods, and business parks
Ethernet over PTP balanced twisted-pair cable is probably the best fit for established
neighborhoods, business parks, and MDUs because it can reuse the ______________.
First mile of existing voice-grade balanced twisted pair cable
Hierarchical Star
The MC (CD) should be close to (if not located in) the main ER (e.g., data center or computer
room).
Ideally, the MC (CD) would:
* Be at the center of the buildings being served.
* Have adequate space for the cross-connect hardware and equipment.
* Have suitable pathways linking it to the other buildings.
NOTE: See the latest edition of BICSI’s OSPDRM for OSP pathway information.
Some of the advantages of using a first level hierarchical star for the campus backbone are
that it:
* Provides a single point of control for system administration.
* Allows testing and reconfiguration of the system’s topology and applications from the
MC (CD).
* Allows easy maintenance and security against unauthorized access.
* Provides increased flexibility.
* Allows the easy addition of future campus backbones
Cross connects
Must not pass thru more than 3 between HCs.
Max of 2 levels from MC to HC
Cross connects should be avoided between _________, although alternate redundant pathways can be designed like this.
HCs
