Cisco Certified Design
(CCDA exam cram)
The use of traffic shaping limit the congestion due to
surges in network traffic. Traffic shaping is used in
ATM, Frame Relay, and other types of networks.
IGMP (Internet Group Management Protocol) is a protocol
used by IP hosts to report their multicast group
memberships to an adjacent multicast router.
LAN related protocols:
IEEE 802.5 in IEEE LAN protocol that uses token passing
access at 4 or 16 MBPS over STP cabling and is similar
to IBM Token Ring.
802.3 uses CSMA/CD.
802.1 describes an algorithm that prevents bridging loops
by creating a spanning tree.
vendorís implementation of HDLC is unique. Cisco's
HDLC uses proprietary, default encapsulation. When you
are using a Cisco router with a non-Cisco router, it is
recommended to use PPP or any standards based
DNS, WINS, DHCP:
DNS is used for resolving domain names to IP addresses
DHCP is used for dynamic assignment of IP addresses
WINS is used for resolving NetBIOS names to IP address
36. FragmentFree switching, as the
name indicates, looks for any bus activity before
forwarding a frame for any possible collisions. This
collision in Ethernet happens during the first 64 bytes.
Therefore, the switch waits for 64 bytes time before
forwarding a frame.
37. Capacity and delays:
At 70% utilization, a WAN link is considered running at
At 40% utilization, an Ethernet link is considered
running at full capacity.
At 80% utilization, a Token Ring network is considered
running at full capacity.
100ms or less should be the response time when a network
is considered working satisfactorily.
The allowable delay for Class II repeater is only 92 bit
times. The allowable delay for a class I repeater is 140
38. VTP is a Layer 2 messaging
protocol. It carries configuration information
throughout a single domain. VTP operates in one of three
VTP Servers can create, modify, or
delete VLANs and other configuration parameters for the
specified VLAN domain.
A VTP client can't create, change,
or delete VLANs.
A VTP transparent mode is used when
a switch is not required to participate in VTP, but only
pass the information to other switches. Transparent
switches don't work either as Server or clients.
Configurations made to a single
switch, called VTP server, are propagated across the
switch fabric under a single domain control. Other
switches, configured as VTP clients, learn the
configuration information from the server.
39. TCP is a full-duplex,
connection-oriented protocol. It incorporates error
checking as well.
UDP (User Datagram Protocol): UDP
is a thin protocol. UDP is a connectionless protocol. It
doesn't contact the destination before sending the
packet and doesn't care whether the packet is reached at
the destination. UDP uses port number 6.
The port number used by TCP is 6
and that of UDP is 17.
40. Cisco uses TFTP protocol to
distribute IOS over a WAN link.