Chapter 11 Configuring Quality of Service on the ML-Series Card

Understanding QoS

Figure 11-1 IP Precedence and DSCP

Bits

0

1

2

3

4

5

6

7

Bits

0

1

2

3

4

5

6

7

DS-Field

DSCP

CU

Precedence

Type of Service

MBZ

Class Selector

Currently

 

Codepoints

 

 

Unused

RFC 1122

 

 

Differentiated Services Code Point

AFC 2474

Bits (0-2): IP-Precedence Defined 111 (Network Control)

110 (Internetwork Control)

101 (CRITIC/ECP)

100 (Flash Override)

011 (Flash)

101 (Immediate)

001 (Priority)

000 (Routine)

DTR-Bits

Must

 

be

RFC 1349

zero

 

Bits (3-6): Type of Service Defined 0000 (all normal)

1000 (minimize delay)

0100 (maximize throughput)

0010 (maximize reliability)

0001 (minimize monetary cost)

96499

Ethernet CoS

Ethernet CoS refers to three bits within a four byte IEEE 802.1Q (VLAN) header used to indicate the priority of the Ethernet frame as it passes through a switched network. The CoS bits in the IEEE 802.1Q header are commonly referred to as the IEEE 802.1p bits. There are three CoS bits that provide eight classes, matching the number delivered by IP precedence. In many real-world networks, a packet might traverse both Layer 2 and Layer 3 domains. To maintain QoS across the network, the IP ToS can be mapped to the Ethernet CoS and vice versa, for example, in linear or one-to-one mapping, because each mechanism supports eight classes. Similarly, a set of DSCP values (64 classes) can be mapped into each of the eight individual Ethernet CoS values. Figure 11-2is an IEEE 802.1Q Ethernet frame, which consists of a 2-byte Ethertype and a 2-byte tag (IEEE 802.1Q Tag) on the Ethernet protocol header.

Figure 11-2 Ethernet Frame and the CoS Bit (IEEE 802.1p)

IEEE 802.1p

(3 bits)

CoS

CFI

 

 

 

 

VLAN ID

IEEE 802.1Q Tag

6Destination Address

6Source Address

2 Type=8100

2Tag Control Information

2Type/Length

42~1500

PAD

 

MAC DATA

 

 

4

FCS

96496

Cisco ONS 15310-CL and Cisco ONS 15310-MA Ethernet Card Software Feature and Configuration Guide R8.5

 

78-18133-01

11-3

 

 

 

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Cisco Systems 15310-CL, 15310-MA manual Ethernet CoS, 11-3

15310-CL, 15310-MA specifications

Cisco Systems has established itself as a leader in the networking domain, offering a wide array of solutions to meet the needs of modern businesses. Among its impressive product lineup are the Cisco 15310-CL and 15310-MA routers, designed to provide advanced network performance and reliability.

The Cisco 15310-CL is a versatile platform that primarily serves as a carrier-class router aimed at supporting high-speed data and voice services. It is built to handle the demands of large enterprises and service providers, offering a robust design that ensures maximum uptime and performance. One of its standout features is its modular architecture, which enables users to customize their configurations based on specific application needs. This scalability allows for future expansion without the need for a complete hardware overhaul.

Key technologies integrated into the Cisco 15310-CL include high-density Ethernet interfaces and a comprehensive suite of Layer 2 and Layer 3 protocol support. The device is capable of supporting multiple types of connections, including TDM, ATM, and Ethernet. This flexibility makes it an ideal choice for organizations that require seamless migration between various service types. Moreover, with features such as MPLS (Multiprotocol Label Switching) support and advanced Quality of Service (QoS) mechanisms, the router ensures that critical applications receive the necessary bandwidth and low latency required for optimal performance.

In contrast, the Cisco 15310-MA focuses on access solutions, providing a cost-effective entry point for businesses looking to enhance their network capabilities. It is well-suited for smaller offices or branch locations that need reliable connectivity without the expense and complexity associated with larger systems. The device supports a range of access methods and provides essential features like firewall capabilities, VPN support, and comprehensive security measures to protect sensitive data.

Both models benefit from Cisco's commitment to security and manageability, offering features like enhanced encryption protocols and user authentication mechanisms that help safeguard networks against threats. Additionally, they can be managed through Cisco’s intuitive software tools, simplifying configuration and monitoring tasks for IT administrators.

The Cisco 15310-CL and 15310-MA are ideal solutions for businesses seeking to enhance their network infrastructure, ensuring firms can keep pace with evolving technology demands while maintaining a focus on security and performance. Their combination of advanced features, modular capabilities, and robust support makes them valuable assets in the networking landscape.