Cisco Certified Design Associate (CCDA exam cram)

31. 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.

32. IGMP (Internet Group Management Protocol) is a protocol used by IP hosts to report their multicast group memberships to an adjacent multicast router.

33. LAN related protocols:

1.      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.

2.      802.3 uses CSMA/CD.

3.      802.1 describes an algorithm that prevents bridging loops by creating a spanning tree.

34. HDLC:

Each vendor’s 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 encapsulation.

35. DNS, WINS, DHCP:

1.      DNS is used for resolving domain names to IP addresses

2.      DHCP is used for dynamic assignment of IP addresses

3.      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 full capacity.

-         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 bit times.

38. VTP is a Layer 2 messaging protocol. It carries configuration information throughout a single domain. VTP operates in one of three modes:

1.      Server mode

2.      Client mode

3.      Transparent mode

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.