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Physical Interface Modules Overview

Table 13: PIM Ter ms (continued)

Ter m Definition

dial-on-demand-routing

(DDR) backup

Feature that provides a J-series Services Router with full-time connectivity across

an ISDN line. When routes on a primary serial T1, E1, T3, E3, Fast Ethernet, or

PPPoE interface are lost, an ISDN dialer interface establishes a backup connection.

To save connection time costs, the Services Router drops the ISDN connection after

a configured period of inactivity. Services Router with ISDN interfaces support two

types of dial-on-demand routing backup: on-demand routing with a dialer filter and

dialer watch. See also dialer filter; dialer watch .

dialer watch Dial-on-demand routing (DDR) backup feature that provides reliable connectivity

without rely

ing on a dialer filter to activate the ISDN interface. The ISDN dialer

interface monitors the existence of each route on a watch list. If all routes o n the

watch list are lost from the routing table, dialer watch initiates the ISDN interface f or

failover co

nnectivity. See also dial-on-demand routing backup .

“dying gasp” notification Ability of a Services Router with a digital subscriber line (DSL) connection that

has lost power to send a message informing the attached DSL access multiplexer

(DSLAM)thatitisabouttogooffline.

ePIM

Enhanced PIM. A particular type of high-speed PIM, such as the Gigabit Ethernet ePIM

or 4-port Fast Ethernet ePIM, which can be inserted only in high-speed slots (slots 3

and 6 on a J4350 Services Router, or slots 2, 3, 5, and 6 on a J6350 Services Router).

floating static route Route with an administrative distance greater than the administrative distance of the

dynamically learned versions of the same route. The static route is used only when

the dynamic routes are n o longer available. When a floating static route is configured

on an interface with a dialer filter, the interface can be used for backup.

ISDN S/T interface Interface between an ISDN network and a network termination device consisting of

two twist

ed pairs, one each for transmitting and receiving. The S/T interface usually

resides in the customer premises and operates at 192 Kbps, of which ISDN traffic

accounts for 144 Kbps.

ISDN U interface Single twisted–pair interface line connecting the customer premises unit in an ISDN

network to the central office. A U interface runs at 144 Kbps (128 Kbps for two B

channels and 16 Kbps for the D channel).

plain old telephone

service (POTS)

Standard telephone service that allows limited s peed and bandwidth of 52 Kbps,

which is also know as public switched telephone network (PSTN).

Field-Replaceable PIMs

PIMs are removable and insertable only when the Services Router is powered off.

You can install a PIM into one o f the six slots in the router chassis. If a slot is not

occupied by a PIM, a PIM blank panel must be installed to shield the empty slot and

to allow cooling air to circulate properly through the router.

These Services Routers support the types of PIM s summarized in Table 14 and

described i n the following se cti ons:

Field-Replaceable PIM Summary on page 30

GigabitEthernetePIMsonpage31

Field-Replaceable PIMs 29

1 2 ... 44 45 46 47 48 49 50 51 52 53 54 ... 283 284

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