Virtualization Concepts

Question 1

What are some reasons to add virtualization in the POP and Data Center?

Answer 1

• Reduce CAPEX (Fewer Chassis)
• Reduce OPEX (deploy fewer chassis, simplify topologies)
• Reduce environmental impact

Question 2

What are the two main types of virtualized router entities, as defined by their physical and operational characteristics?

Answer 2

• A Hardware-Isolated Virtual Router (HVR) has hardware-based resource isolation between routing entities.
• A Software-Isolated Virtual Router (SVR) comprises software-based resource isolation between routing entities.

Question 3

Within SVR, what are some models for achieving virtualization?

Answer 3

1. Multiple guest operating systems to overlay on a host operating system.
2. Integrate the virtualization into the kernel itself.
3. Virtualization is in the individual applications.

Question 4

What is the impact of using the SVR overlay model?

Answer 4

Doesn’t scale well because it introduces significant contention of resources and users tend to over provision resources on all SVRs wasting resources.

Question 5

What is the impact of integrating the virtualization in the kernel with SVR?

Answer 5

This model may improve processing performance but suffers from resource contention and increased complexity and instability in the kernel.

Question 6

What is the impact of providing virtualization in the applications with SVR?

Answer 6

Scales better because of lower overhead but complicates a number of issues because the application must some level of virtualization.

Question 7

Does SVR share data plane or control plane resources?

Answer 7

Yes. All SVR models share resources in the data plane, requiring vigilant resource monitoring.

Question 8

Does HVR share data plane and control plane?

Answer 8

No. It dedicates both control and data plane resources on a per-module boundary to individual virtual entities so there is no sharing of resources, other than a lightweight shim layer that provides low-level communication between HVRs.

Question 9

What HVR technology does Cisco IOS XR provide support for?

Answer 9

Secure Domain Routers (SDRs)

Question 10

Define SDR

Answer 10

An HVR technology that provides full isolation between virtual routing instances through the use of Distributed Route Processors (DRPs) for extra control plane resources.

Question 11

How are SDRs defined no a per-slot boundary?

Answer 11

With entire Route Processors (RPs) and Modular Services Cards (MSCs) dedicated to an SDR.

Question 12

Describe Satellite network virtualization

Answer 12

Satellite switches act as extensions to the ASR9k, they are under the complete control and configuration management of the host router.

Question 13

What is the main advantage to using Nv?

Answer 13

Port Density - A single 24-port Ten Gigabit Ethernet line card on the Cisco ASR 9000 Series Router could integrate up to 24 satellite switches each with 44 GigE ports; this results in an effective port density of 1056 Gigabit Ethernet ports for each Cisco ASR 9000 Series Router line card slot.

Question 14

What types of topologies are supported by the Satellite System?

Answer 14

Hub and Spoke network topology

Dual Home network topology

Simple Ring topology

Layer 2 Fabric network topology

Question 15

Does the Nv switch have to be co-located with the host router?

Answer 15

No, they can be in geographically distinct locations

Question 16

What is NFV?

Answer 16

Network Function Virtualization - decouples network functions from hardware and puts them in software. Example: vFirewalls, vRouters, load balancer, etc.

Question 17

In Long term evolution (LTE), what is the UE?

Answer 17

User equipment like a cellphone. Each UE carries a Universal integrated circuit card (UICC) In LTE the cellphone carries a Subscriber Identity module (SIM) which identifies a phones number, billing plan, etc.

Question 18

Describe eNobeB

Answer 18

eNB are base stations that control the mobile nodes in one or more calls. Also called eNB. These are base stations that control the mobile nodes in one or more calls. A base station that is supporting a specific mobile node is reference as the mobile node’s “serving eNB”. LTE mobile nodes can only communicate with one base station at a time.

Question 19

What are the 2 primary functions of eNB?

Answer 19

Send/receive radio transmissions and to control low-level signaling such as handover commands.

Question 20

Why are eNBS connected to each other?

Answer 20

To support mobility events for packet forwarding and handover using the X2 interface.

Question 21

What interface does the eNB use to communicate with upstream networks?

Answer 21

S1 interface.

Question 22

How do UEs talk to eNBs?

Answer 22

Via the LTE-Uu interface.

Question 23

Describe RAN

Answer 23

(Radio Access Network) This is a way of providing backhaul from access networks to the provider’s core network.

Question 24

What is UMTS?

Answer 24

Universal Mobile Telecommunications System - This was the third generation 3G network upon which 4G LTE was built. This was a combination of circuit and packet switched architectures which was more hierarchical.

Question 25

What is E-UTRAN?

Answer 25

Evolved UMTS Terrestrial RAN. This encompasses the entire LTE access network, which consists of eNB radios.

Question 26

What is BTS?

Answer 26

Base transceiver station - eNB, is the element in E-UTRA of LTE that is the evolution of the element Node B in UTRA of UMTS. It is the hardware that is connected to the mobile phone network that communicates directly wirelessly with mobile handsets (UEs), like a base transceiver station (BTS) in GSM networks.