TDM relies on Layer 3 protocols to operate.
Multiple channels can transmit over a single link.
Original data streams must be reconstructed at the destination.
TDM methods vary depending on the Layer 2 protocol that is used.
It allows information from multiple channels to be allocated bandwidth on multiple wires.
DTE/DCE interface on the device connecting to the Internet
Location of the firewall or router
Physical point at which the public network ends and the private customer network begins
Tag assigned to the physical block where a cross-connect occurs
EIA/TIA 232 (RS-232)
EIA/TIA 422 (RS-422)
EIA/TIA 423 (RS-423)
Parallel connections do not support error checking.
Parallel connections are subject to excessive attenuation.
Parallel connections are subject to clock skew and to crosstalk between wires.
Parallel connections transmit over only two wires and therefore transmit data more slowly.
HDLC does not support CDP.
HDLC and PPP are compatible.P.
HDLC supports PAP and CHAP authentication.
HDLC implementation in Cisco routers is proprietary.
HDLC is the default serial interface encapsulation on Cisco routers.
HDLC uses frame delimiters to mark the beginnings and ends of frames.
It is responsible for negotiating link establishment.
It negotiates options for Layer 3 protocols running over PPP.
It uses MD5 encryption while negotiating link establishment parameters.
It terminates the link upon user request or the expiration of an inactivity timer.
It can test the link to determine if link quality is sufficient to bring up the link.
It monitors the link for congestion and dynamically adjusts the acceptable window size.
Dynamic flow control
Compression and network layer address for IP
Connection-oriented or connectionless communication methods
To supply error detection
To establish and terminate data links
To provide authentication capabilities to PPP
To manage network congestion and to allow quality testing of the link
To allow multiple Layer 3 protocols to operate over the same physical link
Layer 2 is down.
LCP, IPCP, and CDPCP negotiations are in progress.
Only the link-establishment phase completed successfully.
Both the link-establishment and network-layer phase completed successfully.
PAP sends passwords in clear text.
PAP uses a 3-way handshake to establish
PAP provides protection from repeated trial-and-error attacks.
CHAP uses a 2-way handshake to establish a link
CHAP uses a challenge/response that is based on the MD5 hash algorithm
CHAP uses repeated challenges for verification.
LCP is in the process of negotiating a link.
LCP and NCP are waiting for CHAP authentication to complete
LCP negotiation has been successful, but NCP negotiation is in progress.
Data is able to flow across this link.
NCP has successfully negotiated
The PAP passwords did not match, so the routers are trying CHAP authentication.
One router has suggested PAP authentication, and the other has accepted
Authentication but suggested CHAP authentication.
One router can only use PAP authentication while the other router can only use
CHAP, so the connection has been rejected.
The router has agreed on IP parameters
The router has negotiated LCP successfully.
The router is negotiating IP compression options.
The router is requesting an IP address from its peer.
The router has accepted IP but not the suggested IP options.
It can communicate more efficiently with other Cisco devices
It is less complex to configure
It has less Layer 2 overhead
It supports authentication
The remote CSU or DSU has failed.
The router is not sensing a CD signal.
A timing problem has occurred on the cable.
The line is not physically connected to the CSU/DSU.
The router configuration contains the shutdown interface configuration command.
Router(config)# hostname R3 R3(config)# username R1 password Cisco R3(config)# interface Serial 0/0/0 R3(config-if)# encapsulation ppp R3(config-if)# ip address 172.16.3.3 255.255.255.0 R3(config-if)# ppp authentication chap
Router(config)# hostname R3 R3(config)# username R3 password Cisco R3(config)# interface Serial 0/0/0 R3(config-if)# encapsulation ppp R3(config-if)# ip address 172.16.3.3 255.255.255.0 R3(config-if)# ppp authentication chap
Router (config)# username Router password Cisco Router (config)# interface Serial 0/0/0 Router (config-if)# clockrate 64000 Router (config-if)# encapsulation ppp Router (config-if)# ip address 172.16.3.1 255.255.255.0 Router config-if)# ppp authentication chap
Router (config)# username R1 password Cisco Router config)# interface Serial 0/0/0 Router (config-if)# clockrate 64000 Router config-if)# encapsulation ppp Router (config-if)# ip address 172.16.3.1 255.255.255.0 Router (config-if)# ppp authentication chap
Interface Serial0/0/0 resets very frequently.
PPP LQM has shutdown the serial interface.
The serial interface has no input or output queues available
The serial interface is not configured for a Layer 2 protocol.
The interface has been administratively shutdown with the shutdown command.