1,T1/E1控制器参数
farming:sf,esf,crc4
line code:AMI,B8ZS,HDBS
The general configuration of T1:framing esf and line-code b8zs
The general configuration of E1:framing crc4 and line-code hbd3
2,SPID
A SPID is the Service profile identifier, which is a number that some service providers use to define the services to which an ISDN device subscribes. The ISDN device uses the SPID when accessing the switch that initializes the connection to a service provider. SPIDS are normally used to identify the ISDN circuit to the ISDN switch by many service providers, but not all.
Contract your ISP for details on whether or not this information needs to be programmed into your equipment
3,dialer watch(拨号监视)
Dialer Watch is a backup feature that integrates dial backup with routing capabilities. Prior dial backup implementations used the following conditions to trigger backup:
Interesting packets were defined at central and remote routers using Dial on Demand routing
(DDR)
Connection loss occurred on a primary interface using a back up interface with floating
static routes
Traffic thresholds were exceeded using a dialer load threshold
Dialer Watch provides reliable connectivity without relying solely on defining interesting traffic to trigger outgoing calls at the central router. Dialer Watch uses the convergence times and characteristics of dynamic routing protocols. Integrating backup and routing features enables Dialer Watch to monitor every deleted route. By configuring a set of watched routed that define the primary interface, you are able to monitor and track the status of the primary interface as watched routes are added and deleted. Monitoring the watched routes is done in the following sequence:
1. Whenever a watched route is deleted, Dialer Watch checks to see if there is at least one valid route for any of the defined watched IP addresses.
2. If no valid route exists, the primary line is considered down and unusable.
3. If a valid route exists for at least one of the defined IP addresses, and if the route is pointing to an interface other than the backup interface configured for Dialer Watch, the primary link is considered up.
4. If the primary link goes down, Dialer Watch is immediately notified by the routing protocol and the secondary link is brought up.
5. Once the secondary link is up, at the expiration of each idle timeout, the primary link is rechecked.
6. If the primary link remains down, the idle timer is indefinitely reset.
7. If the primary link is up, the secondary backup link is disconnected. Additionally, you can set a disable timer to create a delay for the secondary link to disconnect, after the primary link is reestablished.
4,dialer fast-idle seconds
Specifies the amount of time that a connected line remains idle before it is disconnected to allow a second call destined for a second location over this same line to be placed. This command, used on lines for which there is contention, applied to inbound and outbound calls. The line is considered idle when no interesting packets are being sent across it. If the line becomes idle for the configured length of time, the current call is disconnected immediately and the line is available for new calls. The default fast-idle time is 20 seconds. This is an inactivity timer for contended interfaces.
5,Callback-secure
To enable callback security, use the dialer callback-secure interface configuration command. This command affects those users that are not authorized to be called back with the dialer callback-server command. If the username(hostname in the dialer map command) is not authorized for callback, the call will be disconnected if the dialer callback-secure command is configured. If the dialer callback-secure command is not configured, the call will not be disconnected. in either case, callback has not occurred.
6,Backup delay 5 10
The command backup delay 5 10 has two number variables. The first number 5 specifies that if the line protocol on the main interface goes down ,the ISDN link is to take over after 5 seconds. The second number 10 states that if serial0 were to reactivate, BRI0 will continue to remain active for 10 seconds until going back into standby mode. Having a backup system wait a few seconds before kicking in is a smart feature because many times an interface may only fail for a few seconds ,and an ISDN call would not want to be initiated every time a 1 second outage happened. The longer reactivation time is also a good feature, because the original line has to prove that it's capable of staying active for 10 seconds before it will be considered to be reliable again.
7,You need to configure router TK1 for ISDN DDR routing. What command do you use to define interesting packets?
answer:dialer-list
8,The router uses one of three methods to monitor the primary connection and initiate the backup connection when needed, as listed below:
backup interface-This is an interface that stays in standby until the primary interface line protocol is detected as down and then is brought up
floating static route-This backup route has an administrative distance greater than the administrative distance of the primary connection route and therefore would not be in the routing table until the primary interface goes down
dialer watches-dialer watch is a backup feature that integrates dial backup with routing capabilities
9,WFQ
Fair queuing is enabled by default for physical interfaces whose bandwidth is less than or equal to 2.048M and that do not use the following:
X.25 and synchronous data link control(SDLC) encapsulations
Link access procedure banlanced(LAPB)
Tunnels
Loopbacks
Dialer
Bridges
Virtual interfaces
10,The HQ TestKing router is using subinterfaces on the frame relay interface. What's true about configuring Frame Relay subinterfaces?
a. The configuration must be added to the D channel
b. The physical interface and subinterface can each be configured with IP addresses
c. Subinterface is configured either multipoint or point-to-point
d. Any IP address must be removed from the subinterface
e. none of the above
answer:c
CISCO Self Study:if the physical interface has an address, frames will not be received by the local subinterface
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