Foundation Summary

The "Foundation Summary" is a collection of tables and figures that provide a convenient review of many key concepts in this chapter. For those of you already comfortable with the topics in this chapter, this summary could help you recall a few details. For those of you who just read this chapter, this review should help solidify some key facts. For any of you doing your final prep before the exam, these tables and figures are a convenient way to review the day before the exam.

Table 2-21 lists the IOS classification and marking tools, along with a few key features that differentiate the tools.

Table 2-21 Comparison of Classification and Marking Tools

Table 2-21 lists the IOS classification and marking tools, along with a few key features that differentiate the tools.

Table 2-21 Comparison of Classification and Marking Tools

Tool

Other Functions Besides Class and Mark

Fields That Can Be Examined for Classification

Fields That Can Be Marked*

Policy-based routing (PBR)

Routing packets based on something besides destination address

ACLs indirectly through route maps

IP ToS field IP Precedence field QoS Group

Committed access rate (CAR)

Policing

IP ACLs QoS Group IP DSCP

IP Precedence IP DSCP QoS Group MPLS Experimental

Class-based marking (CB marking)

Any markable fields Input interface MAC addresses All NBAR-enabled fields

IP precedence DSCP 802.1P CoS ISL Priority ATM CLP Frame Relay DE MPLS Experimental QoS Group

Network based application recognition (NBAR)

Statistical information about traffic mix; recognition of applications that use the dynamic port

Extensive list (see Chapter 3, "Classification and Marking")

None; used in conjunction with CB marking

VoIP dial peers

Call routing for VoIP

None

IP Precedence

All claims about features/functions that may be affected by IOS versions assume version 12.2, unless otherwise stated.

All claims about features/functions that may be affected by IOS versions assume version 12.2, unless otherwise stated.

Table 2-22 outlines the key features of IOS queuing methods.

Table 2-22 Comparison of Queuing Tools

Table 2-22 outlines the key features of IOS queuing methods.

Table 2-22 Comparison of Queuing Tools

Tool

Maximum Number of Queues

Classification Capabilities

Queue Service Algorithm/End Result of Algorithm

Priority Queuing

(PQ)

4

IP ACL* Input interface Fragments

Strict service; always serves higher-priority queue over lower queue.

Custom Queuing (CQ)

16

IP ACL* Input interface Fragments

Serves a configured number of bytes per queue, per round-robin pass through the queues. Result: Rough percentage of the bandwidth given to each queue under load.

Weighted Fair Queuing (WFQ)

4096

Automatic, based on flows. (Flow identified by source/destination address and port numbers, plus protocol type)

Each flow uses a different queue. Queues with lower volume and higher IP precedence get more service; high volume, low precedence flows get less service.

Class-Based Weighted Fair Queuing (CBWFQ)

Same as CB marking

Service algorithm not published; results in set percentage bandwidth for each queue under load.

Low Latency Queuing

N/A

Same as CBWFQ

LLQ is a variant of CBWFQ, which makes some queues "priority" queues, always getting served next if a packet is waiting in that queue. It also polices traffic.

IP RTP Priority

N/A

Even UDP ports between 16384 and 32767 (all VoIP payload ports)

An added feature with WFQ or CBWFQ, all VoIP payload is placed in a special "priority" queue, always getting served next if a packet is waiting in that queue.

Modified Deficit

Round-Robin

(MDRR)

8

IP precedence

Similar to CQ, but each queue gets an exact percentage of bandwidth. Supports LLQ mechanism as well.

Some queuing tools support different configuration tools that allow matching the same fields that an ACL can match. In these cases, only the IP ACL method of matching is listed in this summary table.

Some queuing tools support different configuration tools that allow matching the same fields that an ACL can match. In these cases, only the IP ACL method of matching is listed in this summary table.

Figure 2-24 depicts the typical points in a network where policing and shaping are typically deployed.

Figure 2-24 Traffic Policing and Shaping

Step 4: 1 1500 Byte Packet Takes Less Than 100 ms at 128 kbps; Queue Does Not Form on FRS2

FRS2

Queue Does Not Back up on FRS2

Step 3: FR Switch Polices Allowing 1 1500 Byte Packet per 200 ms

FRS3

Discarded

Step 2: R3 Shapes: 1 1500 Byte Packet per 100 ms

Step 1: 50 Packets Arrive at About the Same Time

E000 I

Table 2-23

Table 2-23 outlines the key features of IOS policing and shaping tools.

Comparison of Shaping and Policing Tools

Table 2-23 outlines the key features of IOS policing and shaping tools.

Comparison of Shaping and Policing Tools

Tool

Policer or Shaper

Interfaces Supported

Per Subinterface, and Per VC, Suppor

t

Class-based policing (CB policing; sometimes just called policer)

Policer

All that are supported by Cisco Express Forwarding (CEF)

Per subinterface

Committed access rate (CAR)

Policer

All that are supported by CEF

Per subinterface

Class-based shaping

Shaper

All that are supported by CEF

Per subinterface

Generic traffic shaping/ distributed traffic shaping (GTS/DTS)

Shaper

Frame, ATM, SMDS, Ethernet

Per subinterface

Frame Relay traffic shaping (FRTS)

Shaper

Frame

Per DLCT

Table 2-24 lists the tools, and the various points for comparison, for congestion-avoidance tools.

Table 2-24 Comparison of Congestion-Avoidance Tools

Table 2-24 lists the tools, and the various points for comparison, for congestion-avoidance tools.

Table 2-24 Comparison of Congestion-Avoidance Tools

Tool

Can Be Enabled in IOS?

Weights Based on IP Precedence or DSCP?

Considers Flow Information When Deciding to Drop Packets?

Random Early Detection (RED)

No

No

No

Weighted Random Early Detection (WRED)

Yes

Yes

No

Flow-Based Random Early Detection (FRED)

Yes

Yes

Yes

All functions listed are based on 12.2 mainline IOS code levels.

All functions listed are based on 12.2 mainline IOS code levels.

Table 2-25 lists the link-efficiency tools and some of the pertinent comparison points.

Table 2-25 Comparison of Link-Efficiency Tools

Table 2-25 lists the link-efficiency tools and some of the pertinent comparison points.

Table 2-25 Comparison of Link-Efficiency Tools

Tool

Data Links Supported

Types of Packets to Which Tool Can Be Applied

Payload compression

All; recommended on serial links (T/1, E/1, and slower)

All IP packets

RTP header compression (cRTP)

All; recommended on serial links (T/1, E/1, and slower)

All packets with IP/UDP/RTP headers

TCP header compression

All; recommended on serial links (T/1, E/1, and slower)

All IP packets with TCP headers

Multilink PPP fragmentation and interleaving (MLPPP LFI)

Multilink PPP

All packets larger than a configured length

Frame Relay fragmentation (FRF*)

Frame Relay

All packets larger than a configured length (FRF. 12) or all non-VoFR frames (FRF. 11c)

Link fragmentation and interleaving for Frame Relay and ATM VCs

Frame Relay and ATM

All IP packets

Table 2-26 lists each of the specific CAC tools.

Table 2-26 Comparison of CAC Tools

Table 2-26 lists each of the specific CAC tools.

Table 2-26 Comparison of CAC Tools

Tool

CAC Type

CAC Decision Is Based on Whether . . .

Physical DS0 limitation

Local

A DS0 channel is available on a trunk

Max-connections

Local

A configured number of maximum connections on the dial peer used for the call has been exceeded

Voice-bandwidth for Frame Relay

Local

VoFR PVC CIR has been exceeded; VoFR only (not VoIP)

Trunk conditioning

Local

Keepalives sent to other end of network keep working or not; used for "connection trunk" calls only*

Local Voice Busy-Out (LVBO)

Local

One or more local interfaces fail; if they all fail, no IP connectivity would exist, so the trunk is placed in busy-out state

Advanced Busy-Out Monitor (AVBO)

Measurement based

Probe measurements are better than a configured "impairment factor"; if value is higher, the entire trunk is placed in busy-out

PSTN Fallback

Measurement based

Probe measurements are better than a configured "impairment factor"; instead of busying-out the trunk, calls are allowed or rejected on a call-by-call basis

Resource Availability Indicator (RAI)

Resource based

Terminating gateway's calculation of available DSPs and DS0s implies it has adequate number of resources or not

Gatekeeper Zone Bandwidth (GK Zone Bandwidth)

Resource based

Gatekeeper believes that the bandwidth into the zones in question has been oversubscribed or not

Resource Reservation Protocol (RSVP)

Resource based

The RSVP reservation request flow can, both at call setup and ongoing throughout the call, reserve the needed bandwidth on all RSVP-supporting links in the IP network

* Trunk conditioning acts like a measurement-based CAC tool in my opinion; the IOS documentation, and the DQOS course, list this CAC tool as a local CAC tool. Cisco QoS exam questions are not based on my opinion, so it is listed as a local CAC tool in this book!

* Trunk conditioning acts like a measurement-based CAC tool in my opinion; the IOS documentation, and the DQOS course, list this CAC tool as a local CAC tool. Cisco QoS exam questions are not based on my opinion, so it is listed as a local CAC tool in this book!

Table 2-27 lists Cisco QoS management tools along with a short description of the functions of each tool.

Table 2-27 QoS Management Tools

Tool

Features

QoS Device Manager (QDM)

Uses code that is stored in Flash memory, running inside each router; user can use a web browser to manage QoS configuration and view statistics for an individual router. The product is free.

QoS Policy Manager (QPM)

Application runs on Windows NT or Windows 2000, accessible by a browser. Enables the engineer to manager QoS policies network wide; QPM takes policies and creates QoS configurations, stages, implements, and allows back-out of QoS configurations throughout the network.

Service Assurance Agent (SAA)

The feature formerly known as Response Time Reporter (RTR), SAA is a feature of IOS. This feature can be configured to create, send, respond to, and measure the performance of probe packets. Measurement-based CAC mechanisms create SAA probes on routers; the routers send and receive the probes; and then the routers tell SAA the results.

Internetwork Performance Monitor (IPM)

Formerly a separate product, this Cisco Works feature monitors network performance in real time. It also provides an easy GUI interface to configure SAA probes.

Service Management Solution (SMS)

SMS is a feature of Cisco Works that provides performance statistics similar to IPM, but with the intent to save historical data and to provide reporting about whether configured service level agreements (SLAs) are being met. IPM is used for operating the network and looking at current network statistics; SMS is used for historical reporting, trending, and SLAs.

Cisco has created a QoS framework that shows the various components of a network relating to QoS. Figure 2-25 shows the Cisco QoS framework.

Figure 2-25 The Cisco QoS Framework

Mission Critical Services

Multimedia Video Conference, Collaborative Congesting intServ

DiffServ

MPLS

Signaling Techniques (RSVP, DSCP*, ATM (UNi/NNi))

Hybrid

Classification & Marking Techniques (DSCP, IP Precedence, NBAR, etc.)

Congestion Avoidance Techniques (WRED)

Traffic Conditioners (Policing, Shaping)

Congestion Management Techniques (PQ, CQ, WFQ, CBWFQ, LLQ)

Link Efficiency Mechanisms (Compression, Fragmentation)

Frame Relay

PPP HDLC

SDLC

ATM, POS

FE, Gig E 10Ge

Wireless Fixed, Mobile

Broadband Cable, xDSL

VPNs

A flow consists of all the packets about which the following are true:

• All packets use the same transport layer protocol (for instance, UDP or TCP).

• All packets have the same source IP address.

• All packets have the same source port number.

• All packets have the same destination IP address.

• All packets have the same destination port number.

Packets can be classified and marked near the ingress points of traffic into the network; the QoS tools in the center of the network can just look for the marked field in the packet header, as shown in Figure 2-26.

Figure 2-26 GOCS Design: Mark Packets near the Edge of the Network

Mark Packet in One of the "QoS" Marking Fields

Mark at Ingress

Mark on Switch if Possible

Id kti

___i L May Apply Different

□Hunumt-j-mi QoS Tools, Using

Different Parameters in m id

Classify Easily Based on Previously Marked Fields

Mark Packet in One of the "QoS" Marking Fields

Mark at Ingress

Mark on Switch if Possible in m id

Classify Easily Based on Previously Marked Fields

R3 SW2

Server 1

"1

R3 SW2

Marked with QoS=1: Lots of Flows to Serverl Web Server

Marked with QoS=2: Lots of Flows to Serverl FTP Server

Marked with QoS=3: Lots of VoIP Payload Flows

Marked with QoS=4: Lots of VoIP Signaling Traffic

Table 2-28 summarizes the key points from the GOCS model. Although the exams do not actually cover anything called the GOCS model, the core concepts do provide background information about DiffServ and IntServ.

Table 2-28 Summary of GOCS Features

Table 2-28 summarizes the key points from the GOCS model. Although the exams do not actually cover anything called the GOCS model, the core concepts do provide background information about DiffServ and IntServ.

Table 2-28 Summary of GOCS Features

Feature

Comments

Flow

A flow is a unidirectional set of packets, sent from one source IP address and port, to one destination IP address and port, using the same transport layer protocol.

Flow-based QoS tools

Flow-based tools automatically recognize flows without explicit classification configuration. Each flow can be treated differently, providing a great amount of granularity for QoS.

Class-based QoS tools

Class-based tools treat packets differently based on the category or class to which they belong. The number of classes chosen in a typical network is small (typically fewer than 10). Network engineers choose which types of packets are placed into each class, so class-based QoS tools require explicit configuration of classification parameters.

QoS tools that are neither flow or class based

Some QoS tools operate on all traffic entering or exiting an interface. Other tools may work on a predetermined type of traffic. For example, compressed RTP only operates on packets with RTP headers. Therefore, some tools do not need to consider flows or explicitly defined classes.

QoS class planning— enterprise

For a single enterprise network, a considered, thorough analysis of the network can yield a relatively small set of useful QoS packet categories. Agreement to these categories should occur before beginning the classification and marking strategy of marking near the edge.

Classification and marking

Packets should be classified and marked near the edge of the network, as packets enter the network. By doing so, classification configuration on the remaining routers in the packets' path is simplified, reducing processing overhead, complexity, the risk of misconfiguration.

QoS class planning— Internet

For the Internet, anything more than a handful of general class conventions is unlikely to be agreed upon by a large number of ISPs and customers. Cisco suggests a short list with five categories: VoIP payload, video payload, voice/video signaling, important data, and not-so-important important data.

Internet reclassification and re-marking

Between different autonomous systems, reclassification and re-marking may need to occur. If the autonomous systems distrust each other, packets must be matched based on the contents of the various fields in their headers. If the autonomous systems trust each other, and agree on what packets belong to each of the traffic classes, all that may be required is to reclassify and re-mark based on the marked field inside the IP header.

Table 2-29 lists the RFCs that define DiffServ.

Table 2-29 DiffServ RFCs

Table 2-29 lists the RFCs that define DiffServ.

RFC

Title

Comments

2474

Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers

Contains the details of the 6-bit DSCP field in IP header.

2475

An Architecture for Differentiated Service

This is the core DiffServ conceptual document.

2597

Assured Forwarding PHB Group

Defines a set of 12 DSCP values and a convention for their use.

2598

An Expedited Forwarding PHB

Defines a single DSCP value as a convention for use as a low-latency class.

3260

New Terminology and Clarifications for DiffServ

Clarifies, but does not supercede, existing DiffServ RFCs.

Table 2-30 lists the terms and their definitions. This table provides a reference for study for the Cisco QoS exams.

Table 2-30 DiffServ Terminology and Their Definitions

Table 2-30 lists the terms and their definitions. This table provides a reference for study for the Cisco QoS exams.

Table 2-30 DiffServ Terminology and Their Definitions

Term

Definition

Behavior aggregate (BA)

A DS behavior aggregate.

BA classifier

A classifier that selects packets based only on the contents of the DS field.

Classifier

An entity that selects packets based on the content of packet headers according to defined rules.

DS behavior aggregate

A collection of packets with the same DS code point crossing a link in a particular direction.

DS boundary node

A DS node that connects one DS domain to a node either in another DS domain or in a domain that is not DS capable.

DS code point

A specific value of the DSCP portion of the DS field, used to select a PHB.

DS compliant

Enabled to support differentiated services functions and behaviors as defined in [DSFIELD], this document, and other differentiated services documents; usually used in reference to a node or device.

DS ingress node

A DS boundary node in its role in handling traffic as it enters a DS domain.

continues continues

Table 2-30 DiffServ Terminology and Their Definitions (Continued)

Term

Definition

DS field

The IPv4 header ToS octet or the IPv6 traffic class octet when interpreted in conformance with the definition given in [DSFIELD]. The bits of the DSCP field encode the DS code point, whereas the remaining bits are currently unused.

Dropper

A device that performs dropping.

Marker

A device that performs marking.

Meter

A device that performs metering.

MF classifier

A multifield (MF) classifier that selects packets based on the content of some arbitrary number of header fields; typically some combination of source address, destination address, DS field, protocol ID, source port and destination port.

Per-hop behavior (PHB)

The externally observable forwarding behavior applied at a DS-compliant node to a DS BA.

Policing

The process of discarding packets (by a dropper) within a traffic stream in accordance with the state of a corresponding meter enforcing a traffic profile.

Re-mark

To change the DS code point of a packet, usually performed by a marker in accordance with a TCA.

Shaper

A device that performs shaping.

Traffic conditioner

An entity that performs traffic-conditioning functions and which may contain meters, markers, droppers, and shapers. Traffic conditioners are typically deployed in DS boundary nodes only. A traffic conditioner may re-mark a traffic stream or may discard or shape packets to alter the temporal characteristics of the stream and bring it into compliance with a traffic profile.

Table 2-12 contains material reprinted from RFC 2475.

Figure 2-27 puts some of the DiffServ terminology in context.

Figure 2-28 shows two enterprise networks and two ISPs, with examples of several of the DiffServ terms relating to interconnecting networks.

Figure 2-27 Behavior Aggregates and Per-Hop Behavior

Mark

aiaot-i-gxs

-DS Classifier recognizes BAs by a detailed examination of packet headers

- DS Marker sets DSCP fields based on which BA it is a part of

- Best performed near the source

Dropped

Shape

Bit Rate Limit

Classify I ^ Queue iP" en m hi h-^-Ih n j—-j] i C I III bcnn nrm m

-The BA Classifier identifies BAs by looking at the DSCP field -Routers apply PHBs to each BA

-Good QoS design typically implies same BAs throughout network -PHBs may be different on each router and for each BA

Drop

Shape

Bit Rate Limit

Server 1

Server 1

DSCP = AF11: Behavior Aggregate of Flows to Web Server

DSCP

= AF21:

: Behavior Aggregate of Flows to Serverl FTP Server

->-

DSCP

= AF31:

Behavior Aggregate of Lots of VoIP Payload Flows

DSCP

= AF41:

Behavior Aggregate of VoIP Signaling Traffic

->-

Figure 2-28 DiffServ Domains, Regions, and Nodes

DS Region

DS Interior Node

DS Interior Node

DS Domain DS Domain DS Domain DS Domain

Direction of Flow of Packets in This Example

Figure 2-29 shows the fields inside the ToS byte (per RFC 1349) and the DS field (per RFC 2474).

Figure 2-29 IP ToS Byte and DS Field

0-2 3-6 7

IP

TOS Field

Unused

Precedence

IP Header, Before DiffServ

IP Header, After DiffServ

IP Header, Before DiffServ

IP Header, After DiffServ

\

/

TOS Byte

DS Field

Unused

Table 2-31 lists DSCP values useful for QoS tools that only use precedence, and for those that also use DSCP.

Table 2-31 Default and Class Selector DSCP Values

Name of DSCP Class Selector Values Used by IOS

Binary Value

Equivalent Precedence Value (Decimal)

Default

000000

0

CS1

001000

1

CS2

010000

2

CS3

011000

3

CS4

100000

4

CS5

101000

5

CS6

110000

6

CS7

111000

7

The names of the code points in Table 2-14 match parameters found on IOS DiffServ-compliant classification commands. Because an "all-zeros" DSCP called "default" was already defined, there was no need to create a CS0 DSCP name.

Table 2-32 lists the DiffServ AF DSCPs.

Table 2-32 Assured Forwarding DSCP Values—Names, Binary, and Decimal

Table 2-32 lists the DiffServ AF DSCPs.

Table 2-32 Assured Forwarding DSCP Values—Names, Binary, and Decimal

Low Drop Probability Within Class

Medium Drop Probability Within Class

High Drop Probability Within Class

Name/Decimal/Binary

Name/Decimal/Binary

Name/Decimal/Binary

Class 1

AF11 / 10 / 001010

AF12 / 12 / 001100

AF13 / 14 / 001110

Class 2

AF21 / 18 / 010010

AF22 / 20 / 010100

AF23 / 22 / 010110

Class 3

AF31 / 26 / 011010

AF32 / 28 / 011100

AF33 / 30 / 011110

Class 4

AF41 / 34 / 100010

AF42 / 36 / 100100

AF43 / 38 / 100110

Table 2-33 summarizes many of the key points about the various DiffServ PHBs.

Table 2-33 Comparison of DiffServ PHBs

Table 2-33 summarizes many of the key points about the various DiffServ PHBs.

Table 2-33 Comparison of DiffServ PHBs

PHB

Key Components

Names of DSCPs

Best effort (BE)

PHB for getting no specific QoS treatment

DSCP BE (default)

Class selector (CS)

Uses 8 DSCPs, all with binary 0s for the last 3 bits. Used for backward compatibility with IP precedence. Uses "bigger-is-better" logic—the bigger the DSCP, the better the QoS treatment.

CS1, CS2, CS3, CS4, CS5, CS6, CS7

Assured forwarding (AF)

PHB consists of 2 components: queuing to provide a minimum bandwidth to each for 4 different queues, and 3 drop thresholds inside each queue. DSCPs do not always follow the "bigger-is-better" logic.

AF11, AF12, AF13, AF21, AF22, AF23, AF31, AF32, AF33, AF41, AF42, AF43

Expedited forwarding (EF)

PHB also has 2 components: queuing to provide low delay/jitter/loss and a guaranteed amount of bandwidth, and policing to prevent EF from preventing other types of traffic from getting enough bandwidth.

EF

The terms relating to the traffic-conditioning functions of DiffServ should be mostly familiar by now. Table 2-34 summarizes the terms.

Figure 2-30 does not intend to show a flowchart of what happens to every packet as it passes through a DS boundary node, but rather to show some of the possible paths a packet can take.

Table 2-34 Traffic Conditioners

Traffic Conditioner

Explanation

Metering

The metering function measures the traffic rate to determine whether the traffic conforms to the stated contract, or exceeds the traffic contract. Metering typically occurs per class.

Dropping (policing)

If the traffic exceeds the contract, one option is to drop some packets, so that the packets that are allowed through meet the contract. Most implementations for this feature are called policing.

Shaping

If the traffic exceeds the contract, one option is to shape the traffic. Shaping just means to buffer or queue the traffic, slowing it down, so that the resulting sending rate is within the contract.

Marking

A third option for traffic that exceeds the contract is to re-mark the DSCP with a different value. For instance, Platinum AF41 (low drop probability) traffic that exceeds the contract might get re-marked to AF43. In such a case, if congestion were to occur, this packet would more likely be dropped than if not re-marked.

Do nothing

Not actually written down in the RFCs; one option is to allow the traffic to keep moving right along.

Figure 2-30 RFC 2475—Equivalent Diagram of Classifier and Traffic-Conditioner Functions

Figure 2-30 RFC 2475—Equivalent Diagram of Classifier and Traffic-Conditioner Functions

Figure 2-31 shows the general idea behind the IntServ reservation requests.

Figure 2-31 Integrated Services Reservation Requests

Figure 2-31 Integrated Services Reservation Requests

Request 30 kbps, Request 30 kbps, Request 30 kbps, Request 30 kbps,

Low Delay Low Delay Low Delay Low Delay

Request 30 kbps, Request 30 kbps, Request 30 kbps, Request 30 kbps,

Low Delay Low Delay Low Delay Low Delay

Reserve 30 kbps, Reserve 30 kbps, Reserve 30 kbps, Reserve 30 kbps,

Low Delay Low Delay Low Delay Low Delay

The following list summarizes some of the key points about IntServ that you will want to remember for the QoS exams:

• Integrated services defines the need, and suggests mechanisms, to provide bandwidth and delay guarantees to flows that request it. RFC 1633 defines it.

• IntServ contains two components: resource reservation and admission control.

• RSVP, as defined in RFCs 2205 through 2215, provides the IntServ resource reservation function. RFC 2210 specifically discusses RSVP's usage for IntServ.

• With end-to-end RSVP, each intermediate router reserves the needed bandwidth when receiving a reservation request and confirms the request with RSVP reserve messages. If a router in the path does not speak RSVP, it just transparently passes the flow.

• When IntServ has not been implemented end to end, the RSVP messages can be forwarded in the non-IntServ part of the networks. In that case, the non-IntServ networks can either provide best-effort (BE) service, or provide IntServ-DSCP mapping if the intermediate network is a DiffServ domain.

• A router can offload the admission control function to a COPS server.

Advance SEO Techniques

Advance SEO Techniques

Turbocharge Your Traffic And Profits On Auto-Pilot. Would you like to watch visitors flood into your websites by the 1,000s, without expensive advertising or promotions? The fact is, there ARE people with websites doing exactly that right now. How is that possible, you ask? The answer is Advanced SEO Techniques.

Get My Free Ebook


Post a comment