647-874 ARCH Flashcards
When is a FHRP needed?
Only if the design implements Layer 2 between the access switch and the distribution switch. If Layer 3 is supported to the access switch, the default gateway for end devices is at the access level.
What are the 3 layers of the Hierarchical Network Model?
- Access
- Distribution
- Core
What is the function of the Access layer in the Hierarchical network Model?
- Grants user access to network devices.
- In the WAN environment , the access layer for teleworkers or remote sites may provide entry to the corporate network across WAN technology.
What are some examples of devices that would attach to the Access layer?
- PCs (including virtualized desktops)
- IP Phones
- Servers
- Wireless Access Points
What are some of the functions provided by Access Layer devices and what are some generic examples of those types of devices?
- Control traffic by localizing service requests to the access media.
- Must provide connectivity without compromising network integrity.
- Includes:
- WAN Routers
- Firewalls
- PSTN Gateways
- Multilayer or Layer 2 Access Switches
What is the function of the Distribution layer in the Hierarchical network Model?
- Aggregates the wiring closets, using switches to segment workgroups and isolate network problems in a campus environment.
- Aggregates WAN connections at the edge of the campus and provides policy-based connectivity.
- Addresses QoS and Policy-based traffic control.
What are some of the functions provided by Distribution Layer devices and what are some generic examples of those types of devices?
- Control access to resources that are available at the core layer and must, therefore, make efficient use of bandwidth.
- Must address the quality of service (QoS) needs for different protocols by implementing policy-based traffic control to isolate backbone and local environments.
- Includes:
- Multilayer Switches that connect up to Access Layer devices and down to Multilayer Core Switches.
What is the function of the Core layer in the Hierarchical network Model?
- A high-speed backbone, designed to switch packets as fast as possible.
- Must provide a high level of availability and adapt quickly to changes.
- Provides scalability and fast convergence and an integration point for data center virtualization.
- Provides services that optimize communication transport within the network.
- Provides a high speed, layer 3 switching environment using hardware accelerated services.
- Critical for connectivity.
What is another name for the Core Layer?
Backbone
What are some examples of devices that would attach to the Core layer?
- Distribution Layer Devices.
- Servers
What are some of the functions provided by Core Layer devices and what are some generic examples of those types of devices?
- Provide services that optimize communication transport within the network.
- Are expected to provide maximum availability and reliability with minimum packet processing.
- Should be able to maintain connectivity when the circuits that connect them fail.
Includes:
-Multilayer Switches that connect up to Distribution Layer Multilayer Switches and down to Servers/Data Center.
What is Policy-Based Traffic Control?
A function of the Distribution Layer, it enables you to prioritize traffic to ensure the best performance for the most time-critical and time-dependent applications.
What are the three overlapping architectures that Cisco developed as part of a holistic approach to network architecture and design?
- Borderless Networks
- Collaboration
- Virtualization (data center and desktop)
What does the Borderless Networks Architecture address?
-Addresses increasing worker mobility and focuses on connecting anyone from anywhere , using any device, to any resource (securely, reliably, and seamlessly).
What do the Borderless Networks technologies focus on and what are those technologies?
-Providing high-performance secure mobile connectivity.
- Routing
- Switching
- Mobility
- Security
- Application
- Performance
What does the Collaboration Architecture address?
-Addresses the increased need for interaction among companies, including partners and suppliers.
What do the Collaboration technologies focus on and what are those technologies?
-Integrating many different types of communication methods and devices.
- Unified Communications
- Tele???? (? is a placeholder for a variable)
- Conferencing
- Messaging
What are the 3 major business challenges that the Data Center Architecture addresses?
- Business alignment
- Cost and power efficiency
- Risk management and compliance.
What do the Virtualization technologies focus on and what are those technologies?
-Provisioning data storage and computing resources to applications in a highly scalable and resilient manner by leveraging virtualization technology.
- Virtualization
- Unified Fabric
- Unified Computing
What are 2 advantages of virtualization technology?
- Enables more rapid application deployment and more-efficient use of resources, allowing you to do more with the same resources.
- Offers better protection against disasters and outages.
What is a Medianet?
An intelligent network (IN) that is optimized for rich media, such as voice and video.
What are the 6 Medianet services?
- Network Management
- High Availability
- QoS
- IP Multicasting
- Transcoding
- Authentication and Encryption
What are some applications that leverage the Medianet architecture?
- Cisco Unified Communications
- Cisco Digital Media Systems
- Cisco IP Video Surveillance
- Cisco TelePresence
What are the 5 modules you can commonly divide a network up into in order to facilitate gradual implementation and address specific requirements of each individual part?
- Campus
- Data Center
- WAN and MAN
- Branch
- Teleworker
What are the three overlapping Cisco network architectures for the enterprise and what does each do?
- Borderless Networks - Solutions to increase work mobility. It focuses on connecting anyone from anywhere, using any device, to any resource (securely, reliably, and seamlessly).
- Collaboration - Provides a framework that enables new applications to address the need to communicate and collaborate across corporate boundaries, companies, and continents.
- Virtualization - Consolidates network, storage, and computing resources by leveraging virtualization technologies. Enables rapid deployment of new applications and services, scaling of existing services, and optimization of applications through flexible assignment of resources.
What are the three roles of the core layer in a LAN design?
- Provides high speed data transport
- Serves as a fast convergent infrastructure with a high level of redundancy.
- Avoids data manipulation
What three sections provide network infrastructure and services for remote enterprise users?
- Teleworker Branch Section
- Enterprise Branch Section
- Data Center Section
What are three basic steps of the design methodology under PPDIOO?
- Identify customer requirements.
- Key decision makers identify initial requirements
- Typically done in the Prepare phase - Characterize the existing network and sites.
- Gap Analysis
- Network Audit & Analysis
- Typically done in the Plan phase - Design the network topology and solutions.
- Develop detailed design
- Maybe build a prototype network
What are three tasks that are involved in characterizing an existing network?
- Collecting information using the existing documentation and direct organizational input.
- Using tools to analyze network traffic.
- Using tools for automated auditing of the network.
What are the 6 phases of the Cisco formalized Lifecycle?
- Prepare
- Plan
- Design
- Implement
- Operate
- Optimize
What is involved in the Prepare phase?
- Establishing organizational requirements
- Developing a network strategy
- Proposing a high-level conceptual architecture
- Identifying technologies to support the architecture
- Establishing financial justification
What is involved in the Plan phase?
- Identifying initial network requirements based on goals
- Characterizing sites
- Assessing existing networks
- Performing Gap analysis
- Creating a Project plan
What is involved in the Design phase?
Comprehensive, detail design that: - Meets current business and technical requirements - Incorporates specifications to support: - Availability - Reliability - Security - Scalability - Performance Basis for implementation activities.
What is involved in the Implement phase?
- Network components are built according to design specs.
- Avoids disrupting current network if possible
- Avoids creating points of vulnerability
What is involved in the Operate phase?
- Maintain network health through day to day operations
- Monitor:
- Fault detection
- Correction
- Performance
What is involved in the Optimize phase?
- Proactive management of the network
- Identify and resolve issues before they affect the organization.
- May require network redesign if too many problems or errors arise.
Where does Cisco NSF with SSO and redundant supervisors have the most impact in the campus?
Access layer
What hardware supports Cisco IOS Software Modularity?
Cisco Catalyst 6500 Series
NOT
3750
4500
XR
What is NSF?
Nonstop Forwarding (NSF)
A Layer 3 function that works with SSO to minimize the amount of time a network is unavailable to its users following a switchover.
The main objective of Cisco NSF is to continue forwarding IP packets following an RP (Route Processor) switchover.
What routing protocols support NSF?
- EIGRP
- OSPF
- IS-IS
- BGP
What is SSO?
Stateful Switchover (SSO)
Allows the standby route processor (RP) to take control of the device after a hardware or software fault on the active RP.
SSO synchronizes startup configuration, startup variables, and running configuration; and dynamic runtime data, including Layer 2 protocol states for trunks and ports, hardware Layer 2 and Layer 3 tables (MAC, Forwarding Information Base [FIB], and adjacency tables) and access control lists (ACL) and QoS tables.
Available with these devices: 4500 switches 6500 switches 7600 switches Aggregation Services Routers (ASR)
What is Cisco NSF with SSO and how do they work together?
A supervisor redundancy mechanism in Cisco IOS Software that allows extremely fast switchover at Layers 2 to 4.
Designed to maintain a link-up Layer 3 up state during a routing convergence event.
What is the recommended version of STP to use for the enterprise campus?
RSTP - Rapid Spanning-Tree Protocol
What is UDLD and what is the enterprise recommendation regarding it?
Unidirectional Link Detection
Enables devices to monitor the physical configuration of the cables and detect when a unidirectional link exists where bidirectional communication has not been established.
Typically deployed on fiber topologies
Enable UDLD Aggressive mode in all environments where fiber-optic interconnections are used and enable it in Global mode to support every individual fiber-optic interface.
What are some routing protocol issues you may encounter when using EtherChannel?
- OSPF on an IOS switch could detect a failed link in the bundle and increase the link cost which causes a convergence event.
- EIGRP may not change the link cost if there is a failed link in a bundle.
How many links can be in a EtherChannel bundle?
8
What are two control mechanisms for EthernChannel?
- LACP - Link Aggregation Control Protocol (IEEE 802.3ad)
2 PAgP - Port Aggregation Protocol (Cisco Proprietary)
What are the four modes for LACP and what do they do?
- On - Forces it to be turned on. Only works with other ports set to On.
- Active - Puts port in active negotiating state. Works with other ports set to Active or Passive.
- Passive - Puts port in passive negotiating state. Works with other ports set to Active.
- Off - Turns off LACP
What are the four modes for PAgP and what do they do?
- On - Forces it to be turned on. Only works with other ports set to On.
- Desirable - Puts port in active negotiating state. Works with other ports set to Desirable or Auto.
- Auto - Puts port in passive negotiating state. Works with other ports set to Desirable.
- Off - Turns off PAgP
What is ECMP?
Equal Cost Multipath
What are some details of EtherChannel load balancing?
- Load balancing using an alternate input hash can be tuned with the port-channel load-balance command.
- The default input hash value of Layer 3 for the source and destination does not load balance across the links.
- To achieve the best load balancing, use two, four, or eight ports in the port channel.
What are the reasons that passive interfaces should be implemented at distribution layer ports facing the access layer?
- To limit unnecessary peering across the access layer switches when the Layer 2 to Layer 3 boundary is in the distribution layer
- To avoid transit traffic through the access layer in the event of a link or node failure
What are 3 FHRPs?
First Hop Redundancy Protocols (FHRPs)
- HSRP - Hot Standby Router Protocol (Cisco Proprietary)
- VRRP - Virtual Router Redundancy Protocol (Standards Based)
- GLBP - Gateway Load Balancing Protocol (Cisco Proprietary) - Allows packet load sharing among groups of redundant routers.
GLBP can more easily achieve load balancing on the uplinks from the access layer to the distribution layer, and first- hop redundancy and failure protection.
What FHRP does Cisco recommend?
HSRP is the recommended protocol over VRRP because it is a Cisco-owned standard , which allows for the rapid development of new features and functionality before VRRP.
Use VRRP when needing to interoperate with other vendors.
What are some advantages of GLBP in the Distribution Layer?
- GLBP provides all the benefits of HSRP and includes load balancing when VLANs do not span the access switches.
- A convergence event on the uplink affects only half as many hosts as compared to HSRP when VLANs do not span the access switches.
What is a potential issue you may run into when daisy chaining access switches?
There is a danger that black holes will occur in the event of a link or node failure when the distribution interconnection is Layer 3.
What is the best mechanism to prevent unicast flooding issues?
Do not span VLANs across multiple access switches.
Why should you not span VLANs across multiple access switches if possible?
Because it is the best mechanism to prevent unicast flooding issues.
What hardware is supported by the Cisco Power Calculator?
Cisco Catalyst 4500 and 6500 Series
What are some features that the Cisco Catalyst Integrated Security capabilities provide?
- DHCP snooping prevents rogue DHCP activities.
- Dynamic ARP inspection adds security to ARP to minimize the impact of ARP poisoning and spoofing attacks.
- IP source guard prevents IP spoofing using the dynamic ARP inspection table
Which three address blocks are summarizable?
a. 172.16.20.0/ 24 to 172.16.27.0/ 24
b. 172.16.20.0/ 24 to 172.16.23.0/ 24
c. 10.16.0.0/ 16 to 10.31.0.0/ 16
d. 10.16.0.0/ 16 to 10.47.0.0/ 16
e. 2001: 0DB8: C3B7: 10A0::/ 64 to 2001: 0DB8: C3B7: 10DF::/ 64
f. 2001: 0DB8: 1234: FB40::/ 64 to 2001: 0DB8: 1234: FB5F::/ 64
g. 10.96.0.0/ 16 to 10.159.0.0/ 16
b. 172.16.20.0/ 24 to 172.16.23.0/ 24
c. 10.16.0.0/ 16 to 10.31.0.0/ 16
f. 2001: 0DB8: 1234: FB40::/ 64 to 2001: 0DB8: 1234: FB5F::/ 64
What are 2 examples of what bit splitting could be used for?
- OSPF Area Design
2. Summarizable address blocks with convenient role-based subnets
What is a recommended design approach for OSPF?
Originate the default at the edge and redistribute it into dynamic routing.
What is redistribution and some of its characteristics?
Redistribution is a powerful tool for manipulating and managing routing updates, particularly when two routing protocols are present in a network.
- Easy to create routing loops
- Works poorly with an arbitrary mix of routing protocols anywhere.
- Works well with a limited number of redistribution points.
What is Split Horizon?
A routing protocol feature. The idea behind it is that it is counterproductive to advertise information back to the source of that information, because the information may be out of date or incorrect, and because the source of the information is presumed to be better informed.
In what size network does routing design need to be most carefully done?
Large networks.
What three factors are the biggest influences on OSPF scalability?
- Flooding paths and redundancy
- Amount of routing information in the OSPF area or routing domain.
- Number of adjacent neighbors
What are the different routing protocols and what classes do they fall into?
Distance Vector
- RIPv1
- RIPv2
Link State
- OSPF
- IS-IS
Hybrid Link State and Distance Vector
-EIGRP
Path Vector
-BGP
What does IBGP require and why?
IBGP requires a full mesh of peers because it has no other way to prevent looping of routing information.
What is a route reflector?
A BGP route reflector is an IBGP speaker that reflects or repeats routes learned from IBGP peers to some of its other IBGP peers.
What are 3 types of IBGP routers that will receive reflected routes from a route reflector client?
- Nonclient routers
- Other route reflector client routers
- EBGP peers
What technique does SONET use for framing voice and data onto a single wavelength on fiber?
TDM
What is CWDM?
Coarse Wavelength-Division Multiplexing
An optical technology for transmitting up to 16 channels, each in a separate wavelength or color, over the same fiber strand using less-sophisticated and less-costly transceiver designs than DWDM.
What is WDM?
Wavelength-Division Multiplexing
Uses a multiplexer (mux) at the transmitter to place multiple optical signals on a fiber and a demultiplexer (demux) at the receiver to split them off of the fiber.
What is DWDM and CWDM?
Dense Wavelength-Division Multiplexing
Coarse Wavelength-Division Multiplexing
DWDM and CWDM are technologies that increase the information-carrying capacity of existing fiber-optic infrastructure by transmitting and receiving data on different light wavelengths on a single strand of fiber.
CWDM is an optical technology for transmitting up to 16 channels, each in a separate wavelength or color, over the same fiber strand using less-sophisticated and less-costly transceiver designs than DWDM.
What is DWDM?
Dense Wavelength-Division Multiplexing
A core technology in an optical transport network. The concepts of DWDM are similar to those for CWDM except DWDM spaces the wavelengths more tightly, yielding up to 160 channels. The tighter channels are more precise which is why it is more sophisticated and costly than CWDM.
What is SONET?
Synchronous Optical Network (SONET),
A time -division multiplexing (TDM) technique for framing voice and data onto a single wavelength on fiber.
What is SDH?
Synchronous Digital Hierarchy
What is a drawback to using SONET?
It requires provisioning double the protected bandwidth. Bandwidth along SONET is committed as circuits between two points on the ring.
What Ethernet-based services are point-to-point services?
- EPL
- ERS
- EWS