2.5

Question 1

What are ISDN characterizations?

Answer 1

(Integrated Services Digital Network)

1. ISDN can be delivered in two ways: a)BRI b)PRI
2. BRI connection is 2x64kbit/s bearer and 1x16kbit/s signaling
3. PRI connection is delivered over a T1 or E1 and mostly is used as connectivity from the PSTN to large phone systems and broadcasting services like radio.

Question 2

What is T1?

Answer 2

T1 is T-Carrier level 1 which is Time-division multiplexing used in North America, Japan and south Korea and has 24 channels (total speed of 1.54 Mbit/s line rate)

Question 3

What is E1?

Answer 3

E1 is E-Carrier level 1 which has 32 channels (total speed of 2.048 Mbit/s line rate)

Question 4

Whats T3 / E3?

Answer 4

T-Carrier level 3 also known as DS3 (Digital signal 3) is delivered on coax (BNC connectors) and has 28 T1 circuits with full speed of 44.736 Mbit/s.
E3 is 16 E1 circuits with the full speed of 34.368 Mbit/s

Question 5

What is SONET and what are they referenced by?

Answer 5

(Synchronous Optical Networking) It is commonly implemented by carriers on SONET rings usually referenced by OC (optical Carrier)

Question 6

Whats DSL?

Answer 6

Also called ADSL (Asymmetric Digital Subscriber Line) uses telephone line and the download speed is faster than upload speed and the closer the user is to the central office(CO) the faster the speed and has 10000 ft limitation from CO.

Question 7

Whats Metropolitan Ethernet?

Answer 7

It’s used in a MAN that connects your sites with Ethernet but the Ethernet is usually running over a different topology (Pure Ethernet, Ethernet over SDH, Ethernet over MPLS, Ethernet over DWDM)

Question 8

What are cable broadband characterizations?

Answer 8

Broadband is transmission across multiple frequencies and different traffic types like data on the “cable” network. It has High-speed networking (4Mbits/s-250Mbits/s) and support multiple services (Data, voice, cable)

Question 9

What are Dialup characterizations?

Answer 9

It’s network with voice telephone lines. Its really slow. Mostly used for legacy systems or network utility.

Question 10

Whats PRI?

Answer 10

The Primary Rate Interface (PRI) is a telecommunications interface standard used on an Integrated Services Digital Network (ISDN) for carrying multiple DS0 voice and data transmissions between the network and a user.

Question 11

What is satellite communication?

Answer 11

It’s a High-cost communication to a satellite which uses high frequencies (2GHz)

Question 12

What is copper communication?

Answer 12

It’s an inexpensive but easy to install and maintain form of communication with a limited bandwidth availability and used mostly in WANs(like cable modems, DSL, T1/T3) which is often combined with fiber.

Question 13

What is fiber communication?

Answer 13

It’s a high-speed data communication(frequencies of light) with high installation cost compared to copper but can communicate over long distances. It is used in large installation in the WAN core and supports SONET, wavelength division multiplexing.

Question 14

What is wireless communication?

Answer 14

It uses the cellular network (like Wireless WAN, external hotspot or mobile phone) and it’s used in roaming communication like travel and intermitten communication like security system or daily point-of-sale reporting and updates. It is limited by coverage and speed.

Question 15

Whats frame relay?

Answer 15

It’s ac cost-effective WAN types which has the LAN traffic encapsulated into frame relay frames and frames are passed into the “cloud”.

Question 16

Whats ATM?

Answer 16

(Asynchronous Transfer Mode)It offers high throughput, real-time, and low latency (Data, voice, low latency). It has max speed of OC-192 (about 10Gbit/s) but has limitations based on segmentation and reassembly (SAR)

Question 17

Whats MPLS?

Answer 17

(Multiprotocol Label Switching) It keeps the pros of both ATM and Frame relay and the packets through the WAN have a label (routing decisions are easy) but it can use any transport medium or any protocol (IP packets, ATM cells, Ethernet fames) so its increasingly a common WAN technology.

Question 18

Whata re pushing and popping in MPLS?

Answer 18

Labels are “pushed” onto packets as they enter the MPLS cloud and they are “popped” off on the way out.

Question 19

Whats PPP?

Answer 19

(Point-to-point protocol) It creates a network connection between two devices (layer 2) and works almost anywhere (Dial-up, mobile phone, DSL)

Question 20

What is PPP used for?

Answer 20

1. Authentication
2. Compression
3. Error detection
4. Multilink

Question 21

Whats PPPoE?

Answer 21

PPPoE is an extension of PPP that encapsulates the PPP protocol within an Ethernet frame. Common on DSL networks and easy to implement.

Question 22

Whats DMVPN?

Answer 22

(Dynamic Multipoint VPN) It’s mostly in cisco routers and your VPN builds itself. Also tunnels are built dynamically, on-demand ( a dynamic mesh)

Question 23

Whats SIP trunking?

Answer 23

(Session Initiation Protocol) It’s a control protocol for VoIP. Traditional PBX connectivity uses T1 / ISDNbut SIP trunking uses SIP/VoIP to communicate to an IP-PBX provider and its more efficient use of bandwidth (less expensive than ISDN lines and more phone system options.

Question 24

Whats demarcation point?

Answer 24

The point where you connect with the outside world (WAN provider, Internet service provider) also known is demarc and is used everywhere even at home.

Question 25

Whats CSU/DSU?

Answer 25

(Channel Service Unit / Data Service Unit) Its a device between the router and the circuit. CSU connects to the network provider and DSU connects data terminal equipment (DTE). It can be a physical device or built-in to the router.

Question 26

what are CSU/DSU connections?

Answer 26

From the demarc: RJ-48c wiring
to the router: Serial connection (v.35 and RS-232)
sometimes monitor jacks

Question 27

Whats a Smartjack?

Answer 27

The smart jack is a way for your WAN provider to perform some additional functions like built-in diagnostics and Alarm indicators