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http:\\ciscocertifications.info
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100BaseFX - 100BaseFX uses a two strand fiber cable of which one strand transmits and the
other receives. Supports full duplex operation. The max distance is 412 Meters Half Duplex or
2 Kilometers Full Duplex.
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100BaseT4 - 100BaseT4 uses four-pair Cat 3, 4, or 5 UTP cabling and RJ45. Allows the use
of voice grade cabling to run at 100Mbps.
Fast Ethernet has its advantages due to being ten times faster than 10BaseT and can be used on existing
Cat5 cabling using existing Ethernet contention methods. It protects the investment in current cabling
and experience. Fast Ethernet is similar to 10BaseT as follows:
1)
It uses the same MTUs
2)
It is based on the same 802.3 specifications
3)
It uses the same Media Access Control
4)
It uses the same Frame format
*Keypoints:Know the above 4 ways Fast Ethernet is similar to 10BaseT Ethernet.Know that 100BaseT has a distance limitation of 100 meters.Spanning Tree Protocol
Spanning-Tree Protocol is a link management protocol that provides path redundancy while preventing
undesirable loops in the network. For an Ethernet network to function properly, only one active path
can exist between two stations. Multiple active paths between stations cause loops in the network. If a
loop exists in the network topology, the potential exists for duplication of messages. When loops occur,
some switches see the same stations appearing on both sides of the switch. This condition confuses the
forwarding algorithm and allows duplicate frames to be forwarded.
To provide path redundancy, Spanning-Tree Protocol defines a tree that spans all switches in an ex-
tended network. Spanning-Tree Protocol forces certain redundant data paths into a standby (blocked)
state. If one network segment in the Spanning-Tree Protocol becomes unreachable, or if Spanning-Tree
Protocol costs change, the spanning-tree algorithm reconfigures the spanning-tree topology and rees-
tablishes the link by activating the standby path.
Virtual LANs
A VLAN (Virtual Local Area Network) is a switched network that is logically segmented by communi-
ties of interest without regard to the physical location of users. Each port on the Switch can belong to a
VLAN. Ports in a VLAN share broadcasts. Ports that do not belong to that VLAN do not share these
broadcasts thus improving the overall performance of the network. VLANs remove the physical con-
straints of workgroup communications. Layer 3 routing provides communications between VLANs. In
other words users can be in totally different physical locations and still be on the same VLAN. Like-
wise users in the same physical location can be on different VLANs.
VLANs provide the following benefits:
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Reduced administration costs from solving problems associated with moves and changes- As users physically move they just have to be re-patched and enabled into their existing
VLAN
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Workgroup and network security - You can restrict the number of users in a VLAN and
also prevent another user from joining a VLAN without prior approval from the VLAN net-
work management application.