Cisco 300-830 CLCCE flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Webex Calling PSTN options

Cisco-provided PSTN through a Cloud Connected PSTN provider, or a Local Gateway on premises for PSTN and emergency breakout. The choice affects emergency calling and number portability.

Cisco Unified Border Element

A Cisco session border controller that terminates and re-originates SIP signaling and RTP between Unified CM and a service provider or the Webex cloud.

Expressway-C and Expressway-E

Expressway-C sits inside the trusted network toward Unified CM; Expressway-E sits in the DMZ and faces the internet. Together they provide Mobile and Remote Access.

Mobile and Remote Access

A solution where endpoints register to Expressway-C using a traversal zone to Expressway-E, allowing off-network registration without a VPN.

Webex Edge Connect

A private, SLA-backed connection from the customer network to the Webex cloud through a direct connect partner, avoiding the public internet.

UCM Cloud

Cisco-hosted dedicated Unified Communications Manager deployment, distinct from Webex Calling and managed through a Cisco cloud operations portal.

Hybrid services

Connectors such as Hybrid Calendar or directory sync that link on-premises Unified CM data with Webex cloud services for a combined experience.

MRA firewall ports

Expressway-E needs inbound TCP 8443 for client registration, TCP 5060/5061 for SIP, and UDP 3478 for TURN. Expressway-C to Expressway-E uses TCP 7001.

Expressway-E dual interfaces

One interface faces the DMZ and one faces the internal network, with no direct routing between them. The internal interface only reaches Expressway-C.

MRA DNS records

External DNS resolves _collab-edge._tls SRV to Expressway-E public addresses; internal DNS resolves _cisco-uds._tcp for on-premises discovery.

Expressway-E certificate

Must be signed by a public CA and match the cluster FQDN in the subject alternative name, or clients reject the TLS connection.

QoS markings

Voice RTP is marked EF (DSCP 46), call signaling CS3 (DSCP 24), and video AF41 (DSCP 34). Trust boundaries preserve markings across the WAN.

TURN relay

Expressway-E provides TURN relay for MRA media when endpoints are behind NAT, allowing media to traverse firewalls.

Bandwidth per call

G.711 uses about 80 kbps with overhead, G.729 about 24-30 kbps, and Opus adapts. Video calls require substantially more bandwidth.

Expressway cluster size

Expressway clusters support up to six peers for high availability at the edge, with defined fallback order for endpoints.

Unified CM routing order

Translation pattern, then route pattern with digit analysis, then route list, then route group, then gateway or trunk. The first matching pattern wins.

Partitions and CSS

A CSS is an ordered list of partitions that defines which numbers a device can dial. Line CSS overrides device CSS for calls from that line.

Digit analysis specificity

Exact digits beat wildcards; among wildcards, fewer wildcards and more specific digits win. A route pattern with @ matches full E.164 numbers.

Route list failover

The first route group is tried; if all its devices are unavailable, the next route group is used. Route groups select gateways by order or distribution.

Translation pattern rewrite

Rewrites digits using discard digits (predot, preat, strip) and calling or called party transformation masks, and can also set the CSS.

Globalized dial plan

Normalize all numbers to E.164 at the ingress edge with translation patterns, then apply site-specific transformation masks at the egress gateway.

SRST

Survivable Remote Site Telephony on IOS gateways provides local call control fallback when the WAN to Unified CM is lost.

Hunt group algorithms

Hunt groups distribute calls to line members using algorithms such as longest idle, circular, and broadcast. Hunt pilots use a partition and CSS.

Dial peer preference

On IOS gateways, dial peers match inbound and outbound calls with destination patterns; preference values break ties between matching peers.

SIP security

Use TLS for signaling and SRTP for media. Unified CM and Expressway support secure profiles, and MRA uses TLS 1.2 by default.

Unified CM certificates

The tomcat and callmanager certificates must be valid and trusted. Expired or mismatched SANs cause registration and zone failures.

Expressway zone status

Check zone status, traversal zone, and SIP status. A zone not active usually indicates a certificate, DNS, or firewall issue.

Dialed Number Analyzer

A Unified CM tool that simulates call routing to verify how a dialed number is analyzed through partitions, CSS, and route patterns.

RTMT troubleshooting

Cisco Unified Real-Time Monitoring Tool provides alarms, performance counters, and trace and log central for Unified CM troubleshooting.

Common MRA failures

Incorrect external DNS SRV record, missing public certificate SAN, blocked TCP 8443 or UDP 3478, and untrusted certificates between Expressway-C and Unified CM.

CUBE SIP debug

The command debug ccsip messages on CUBE displays SIP messages for troubleshooting call flows between Unified CM and the service provider.

Webex Control Hub

Provides analytics, troubleshooting, and device management for Webex Calling, with call quality data using MOS and jitter and latency metrics.