Packet over SONET

Chapter Description

This sample chapter covers Packet over SONET (PoS) operation, encapsulation, protection, and convergence.

Review Questions

  1. True or False: Packet over SONET was developed because there was no other way to transport data over a SONET network.

    1. True

    2. False

  2. PoS can be directly encapsulated onto the network media. Which of the following is not a method for connecting PoS to network media?

    1. Connectivity to SONET/SDH ADMs

    2. Connectivity to transponders in a DWDM system

    3. Dark-fiber connectivity

    4. ATM connectivity

  3. Which of the following are the three requirements for data to be successfully transported over SONET/SDH?

    1. The use of high-order containment is required.

    2. The PoS frames must be placed inside of the SONET containers aligned on frame boundaries.

    3. The x ^ 43 + 1 scrambler must be used in addition to SONET native scrambling.

    4. The PoS frames must be placed inside of the SONET containers aligned on the octet boundaries.

  4. What is the hex value of an HDLC delimiter flag byte?

    1. 0x7D

    2. 0xE7

    3. 0x7E

    4. 0xFF

    5. 0x03

  5. What does the protocol field inside of the PPP frame indicates?

    1. The protocol that is carrying the PPP frame

    2. The protocol used to decode the FCS field

    3. The protocol used to detect the number of padding bytes found in this frame

    4. The protocol used to format the data in the Information field

    5. None of the above

  6. The C2 byte value of a PoS interface that is using the payload-scrambling function is set to which two of the following values?

    1. 0xCF%

    2. 0x16

    3. 22

    4. 207

    5. 0xFF

  7. It is recommended that the Layer 3 protocol and the SONET protocol configurations should ______.

    1. Have both Layer 3 and SONET in a bidirectional ring configuration

    2. Have Layer 3 in a point-to-point configuration and SONET in a bidirectional ring configuration

    3. Both be in a point-to-multipoint configuration

    4. Both be in a point-to-point configuration

  8. HDLC frames in a PoS environment contain which four fields?

    1. Address, Data, Destination, and Frame Check Sequence

    2. Location, Data, Destination, and Protocol

    3. Location, Control, Information, and Protocol

    4. Address, Control, Information, and Frame Check Sequence

  9. What is the purpose of PGP?

    1. Transport data packets across SONET/SDH links

    2. Overcome routing problems between Layer 3 and the SONET network layer

    3. Reliable end-to-end communication and error-recovery procedures

    4. Achieve adequate transparency, protection against malicious attacks, and enough zero-to-one transitions to maintain synchronization between adjacent SONET/SDH devices

  10. What is the ideal configuration for APS 1+1 to reduce the need for routing updates due to a failure?

    1. One SONET line between the private network router and the service provider ADM

    2. Two SONET lines between one private network router and the service provider ADM

    3. Two routers with one line each to the service provider ADM

    4. PoS Reflector mode

  11. PoS Reflector mode is used for what purpose?

    1. By the working router to keep the distant router up to date

    2. By the protect router to notify the distant router when it takes over for the working router

    3. By the Layer 3 protocol to send routing updates

    4. To send AIS downstream

  12. In which three ways can you interconnect PoS interfaces?

    1. SONET

    2. Dark fiber

    3. Gigabit Ethernet

    4. DWDM

    5. Bidirectional path switched rings (BPSRs)

  13. One of the advantages to PoS is that when there is a network failure, ___________ can restore the network connection before the Layer 3 routing protocol even realizes that there is a problem.

    1. ATM

    2. SDH

    3. APS

    4. IPS