Term
| What are 2 important goals when designing a WAN? |
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Definition
- Application availability - networked apps rely on the network between the client and server to provide its functions to users
- Cost and usage - to select the correct reliable WAN service, you must consider the budget and usage requirements of the WAN service |
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Term
| What are the 3 different types of VPN groups? |
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Definition
- Access VPN - gives user connectivity to their corporate intranets over shared networks (internet). Two architecture options are client-initiated o network access server (NAS)-initiated
- Intranet VPN - or site-to-site VPNs connects remote offices to the head-end offices, usually over their internet connection. Main benefits include reduced WAN infrastructure, lower WAN charges and reduced COO
- Extranet VPN - VPN infrastructure for business partner connectivity using internet or private infrastructure for network access. |
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Term
| What 2 methods exist for tunneling private networks over a public IP network? |
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Definition
- General routing encapsulation(GRE) - developed by Cisco to encapsulate a variety of protocols inside IP tunnels. Approach is simple for basic IP VPNs, but lacks security and scalability. Doesn't provide any encryption to secure packets during transport.
- IP security(IPSec) - provides secure transmission over IP networks. Operates in either tunnel or transport mode. Packet payloads can be encrypted and IPSec receivers can authenticate packets' origin. IKE and PKI can also be used with IPSec |
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Term
| Describe traffic shaping and policing |
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Definition
Traffic shaping slows down the rate at which packets are sent out an interface by matching certain criteria. It used a token bucket technique to release the packets into the output queue at a preconfigured rate
Policing tags or drops traffic depending on the match criteria. Generally, policing is used to set the limit of incoming traffic coming into an interface.
Remember that traffic shaping buffers packets, while policing can be configured to drop packets. |
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Term
| What needs to be deployed when setting up WAN backups over the Internet? |
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Definition
| Secure tunnels using IPSec need to be deployed to protect the date during transport. |
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Term
| What are the 3 enterprise branch profiles for the SONA framework? |
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Definition
- Single-tier design - up to 50 users (small)
- Dual-tier design - up to 100 users (medium)
- Multi-tier-design - between 100 to 1000 users (large) |
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Term
Specify the speeds for the following optical carrier (OC) rates:
1. OC-1
2. OC-3
3. OC-12
4. OC-24
5. OC-48
6. OC-192
7. OC-255 |
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Definition
1. OC-1 = 51.85 Mbps
2. OC-3 = 155.52 Mbps
3. OC-12 = 622.08 Mbps
4. OC-24 = 1.244 Gbps
5. OC-48 = 2.488 Gbps
6. OC-192 = 9.952 Gbps
7. OC-255 = 13.21 Gbps |
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Term
| Describe weighted fair queuing |
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Definition
| WFQ ensures that traffic is separated into individual flows or sessions without requiring you to define ACLs. WFQ uses 2 categories to group sessions; high bandwidth and low bandwidth, where low bandwidth has a priority over high bandwidth. WFQ is the default QoS mechanism on interfaces below 2Mbps |
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Term
| Depending on the speed of the WAN link, what type of load balancing is preferred? |
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Definition
| If WAN links are less than 56 kbps, per-packet load balancing is preferred. For WAN links faster than 56 kpbs, per destination load balancing is preferred. |
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Term
| What are peer-to-peer VPNs? |
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Definition
| Peer-to-peer VPNs use modern MPLS VPN technology. It learns routing information from normal IP routing sources, however they use an additional label to specify the VPN tunnel and the corresponding VPN destination network. |
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Term
| Describe class-based weighted fair queuing |
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Definition
| CBWFQ provides support for modular user-defined traffic classes. It lets you define traffic classes that correspond to match criteria, including ACLs, protocols and input interfaces. Traffic that matches the class criteria belongs to a specific class, which has a defined queue that corresponds to an output interface. CBWFQ is becoming the standard QoS mechanism for networks that are not using VoIP |
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Term
| What is multiprotocol label switching? |
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Definition
| MPLS is technology for the delivery of IP services using labels (numbers) to forward packets. MPLS functions by encapsulating packets with headers that include the label information. As soon as packets are marked with a label, specific paths through the network can be designed to correspond to the distinct label. The goal is to maximize switching using labels and minimize level 3 routing. |
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Term
| Describe virtual private dial up networks (VPDN) |
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Definition
| VPDN provide remote network access using tunnels over traditional dialup, ISDN, DSL, cable, and wireless network access connections. This involves the ISP terminating network connections and then forwarding the traffic onto the company's corporate networks. The virtual tunnels use layer 2 forwarding (L2F) of layer 2 tunneling protocol (L2TP) between company sites and the ISP. |
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Term
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Definition
| Overlay VPNs are built using traditional WAN technologies such as frame relay and ATM. Secure VPN tunnels are built over the IO infrastructure using generic routing encapsulation (GRE) and IPSec protocols. |
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Term
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Definition
| CQ uses up to 16 individual output queues, where byte size limits are applied to each queue so that when th limit is reached, it proceeds to the next queue. |
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Term
| When voice and video are required for small offices, teleworkers, or remote agents, what is the recommended upstream bandwidth? |
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Definition
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Term
| Describe priority queuing |
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Definition
PQ is a queuing method that establishes 4 interface output queues that serve different priority levels; low, medium, high, and default.
Note: PQ can starve other queues if too much data is in one queue. |
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Term
| Describe low-latency queuing |
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Definition
| LLQ adds a strict priority queue to CBWFQ. It allows delay-sensitive traffic such as voice to be sent first. Without LLQ CBWFQ would not have a priority queue for real-time traffic. LLQ is the standard QoS method of choice for VoIP networks. |
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Term
What are the 4 base service categories for Cisco IOS packaging?
What are 3 premium packages of Cisco's IOS package for more complex networking environments? |
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Definition
- IP base - entry-level IOS supporting IP data
- IP voice - supports converged voice and data
- Advanced security - security features and VPN
- Enterprise base - enterprise layer 3 protocols and IBM support
- SP services - adds features such as MPLS, ATM, SSH, and netflow to the lower IP voice package.
- Advanced IP services - adds support for IPv6
- Enterprise services - adds full IBM support |
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Term
| What is dense wave division multiplexing? |
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Definition
| Dense wave division multiplexing (DWDM) increases the fiber optic's bandwidth capabilities by using different wave lengths of light called channels over the same fiber strand |
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Term
| What is the list of Cisco enterprise MAN/WAN architecture? |
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Definition
- Private WAN (optional encryption)
- Private WAN with self deployed MPLS
- ISP service (Internet with site-to-site and remote-access VPN)
- Service provider managed IP/MPLS VPN |
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Term
| What are some common factors that influence decisions for WAN architecture selection? |
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Definition
- high availability
- support for growth
- ongoing expenses
- ease of management
- cost to implement
- network segmentation support
- support for voice and video |
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