junos enterprise switchingluk.kis.p.lodz.pl/ksbg/wyklad/v2017/03 vc lag - jex_11.a... · 2015. 10....

© 2011 Juniper Networks, Inc. All rights reserved. | www.juniper.net | Worldwide Education Services

Chapter 7: High Availability

Junos Enterprise Switching

© 2011 Juniper Networks, Inc. All rights reserved. www.juniper.net | 7-2Worldwide Education Services

Chapter Objectives

After successfully completing this chapter, you will be

able to:

•List and describe features that promote high availability

•Configure and monitor high availability features

•Describe key concepts and components of a Virtual Chassis

•Explain the operational details of a Virtual Chassis

•Implement a Virtual Chassis and verify its operations


Agenda: High Availability

Overview of High Availability Networks

Link Aggregation Groups

Redundant Trunk Groups

Virtual Chassis

•Overview of Virtual Chassis

•Configuring and Monitoring a Virtual Chassis


What Is High Availability?

The ability to ensure a high degree of operational

continuity to a resource for a user community

•Typically measured over a specific period of time

User Community

Resources


High Availability Networks

High availability networks include provisions that allow

for the maximum amount of uptime and accessibility

Increase uptime and accessibility

Decrease downtime

Key Considerations

1. Is the base functionality of the network’s hardware,

software, protocols, and overall operations protected?

2. When a failure occurs, how will the overall system or

network react and what level of recovery can be expected?


High Availability Features

EX Series switches support a number of features to

help increase uptime and availability including:

•Link aggregation groups (LAGs)

•Redundant Trunk Groups (RTG)

•Virtual Chassis

Note: Feature support varies by product; check the product-specific documentation for support details.

User Community

Resources






Virtual Chassis




Link aggregation combines multiple Ethernet interfaces in to a single link layer interface, also known as a link aggregation group (LAG) or bundle

•Defined in the 802.3ad standard

What Is It?

Access

Aggregation

ge-0/0/12

ge-0/0/13

Switch-1 Switch-2

Participating interfaces are

known as member linksCommonly used on

trunk port connections


Benefits of 802.3ad Link Aggregation

Benefits of 802.3ad link aggregation include:

•Increases bandwidth

•Provides link efficiency

•Creates physical layer redundancy

Access

Aggregation

ge-0/0/12

ge-0/0/13

Switch-1 Switch-2


Link Requirements and Considerations

Interface requirements and considerations include:

•Duplex and speed must match

•Up to eight member links per LAG

•Member links do not need to be contiguous ports nor must

they be on the same switch when part of a Virtual Chassis

ge-0/0/13

ae0

ge-0/0/1

Switch-1 Switch-2

ae0

………

ge-0/0/5

ge-0/0/10……


Traffic processing and forwarding considerations:

•RE generated traffic is always sent on the lowest member

link

•IP traffic hashing uses Layer 2, Layer 3, and Layer 4 details

•Non-IP traffic hashing uses source and destination MAC

addresses

Traffic Processing and Forwarding

ge-0/0/13

ae0

ge-0/0/1

Switch-1 Switch-2

ae0

IP traffic

Non-IP traffic

RE traffic

Traffic is shared across

all member links


Link Aggregation Control Protocol

LACP performs link monitoring and controls the

member links that form a single logical channel

You can set the LACP mode as active or passive:

•Active mode initiates transmission of LACP packets

•Passive mode responds to LACP packets

Access

Aggregation

Switch-1 Switch-2

ae0

ae0

ae1 ae1

Passive

Active Active

Note: At least one device must be configured for

active mode for the link to become operational.


Implementing LAGs (1 of 2)

{master:0}[edit chassis]

user@Switch-1# run show interfaces terse | match ae0


user@Switch-1# set aggregated-devices ethernet device-count 1


user@Switch-1# commit

configuration check succeedscommit complete



ae0 up down

Switch-1 Switch-2

ae0 ae0

ge-0/0/12

ge-0/0/13

Create an aggregated Ethernet interface:

Link state remains down until operational

member links are added to LAG


Configure the aggregated Ethernet interface and

associate desired member links with the LAG:

Implementing LAGs (2 of 2)

{master:0}[edit interfaces]

user@Switch-1# set ae0 unit 0 family ethernet-switching


user@Switch-1# set ae0 aggregated-ether-options lacp active


user@Switch-1# set ge-0/0/12 ether-options 802.3ad ae0


user@Switch-1# set ge-0/0/13 ether-options 802.3ad ae0


user@Switch-1# commit

configuration check succeedscommit complete



ge-0/0/12.0 up up aenet --> ae0.0

ge-0/0/13.0 up up aenet --> ae0.0

ae0 up up

ae0.0 up up eth-switch

ae0

Switch-1 Switch-2

ae0

ge-0/0/12

ge-0/0/13


Monitoring LAGs

Use the show interfaces output to determine

state information for aggregated interfaces:

•Note that other commands exist that show similar details

{master:0}

user@Switch-1> show interfaces terse | match ae0

ge-0/0/12.0 up up aenet --> ae0.0

ge-0/0/13.0 up up aenet --> ae0.0

ae0 up up

ae0.0 up up eth-switch

{master:0}

user@Switch-1> show interfaces extensive ae0.0 | find "LACP Statistics:"

LACP Statistics: LACP Rx LACP Tx Unknown Rx Illegal Rx

ge-0/0/12.0 26 516 0 0

ge-0/0/13.0 25 519 0 0

Marker Statistics: Marker Rx Resp Tx Unknown Rx Illegal Rx

ge-0/0/12.0 0 0 0 0

ge-0/0/13.0 0 0 0 0

Protocol eth-switch, Generation: 195, Route table: 0

Flags: None


Test Your Knowledge

Given the sample outputs, can you guess what might

be causing ae0.0 to remain in the down state?{master:0}

lab@Switch-1> show interfaces terse | match ae0

ge-0/0/12.0 up up aenet --> ae0.0

ge-0/0/13.0 up up aenet --> ae0.0

ae0 up down

ae0.0 up down eth-switch

{master:0}

lab@Switch-1> show interfaces extensive ae0.0 | find "LACP Statistics:"

LACP Statistics: LACP Rx LACP Tx Unknown Rx Illegal Rx

ge-0/0/12.0 0 224 0 0

ge-0/0/13.0 0 223 0 0

Marker Statistics: Marker Rx Resp Tx Unknown Rx Illegal Rx

ge-0/0/12.0 0 0 0 0

ge-0/0/13.0 0 0 0 0

Protocol eth-switch, Generation: 195, Route table: 0

Flags: None

•The remote device does not have LACP enabled






Virtual Chassis




What Is It?

A redundant trunk group provides a quick and simple

failover mechanism for redundant Layer 2 links

•Can be used as a replacement for STP on access switches

that are connected to two aggregation switches

Access

Aggregation

ge-0/0/1

ge-0/0/2

Switch-1 Switch-2

Switch-3 Switch-4 Switch-5

RSTP

RTG


Only active link is used to forward traffic, other links

serve as backup links and do not forward traffic

•When active link fails, a backup link becomes active

Backup Link

How Does It Work?

Access

Aggregation

ge-0/0/1

ge-0/0/2

Switch-1 Switch-2

Switch-3

RSTP

RTG

Active Link


Configuration Considerations

RTG is typically only configured on access switches

•RTG and STP are mutually exclusive on a given port

•STP BPDUs received on RTG links are discarded

•STP is configured on aggregation switches

Access

Aggregation

ge-0/0/1

ge-0/0/2

Switch-1 Switch-2


RSTP

RTG

Note: A maximum of 16 redundant trunk groups per switch.

ge-0/0/8ge-0/0/10


Case Study: Topology and Objectives

Access

Aggregation

Switch-1 Switch-2

Switch-3

Objectives:

•Implement RTG on Switch-3 to ensure that only a single path

is available toward the aggregation switches

•Ensure that Switch-3 forwards user traffic out ae0.0

whenever it is operational


Case Study: Configuring RTG

{master:0}[edit ethernet-switching-options]

user@Switch-3# set redundant-trunk-group group rtg-1 interface ae0.0 primary


user@Switch-3# set redundant-trunk-group group rtg-1 interface ge-0/0/10.0


user@Switch-3# show

redundant-trunk-group {

group rtg-1 {

interface ge-0/0/10.0;

interface ae0.0 {

primary;

}

}

}

You configure RTG under the [edit ethernet-

switching-options] hierarchy:

Access

Aggregation

Switch-1 Switch-2

Switch-3

Note: If primary knob is omitted, highest-numbered interface initially becomes active link but does not

preempt lower-numbered interfaces functioning as the active link in failure and recovery scenarios

Interface marked as primary is

always active when operational


Case Study: Monitoring RTG

{master:0}

user@Switch-3> show redundant-trunk-group

Group Interface State Time of last flap Flap

name count

rtg-1 ae0.0 Up/Pri/Act Never 0

ge-0/0/10.0 Up Never 0

Use show redundant-trunk-group to monitor

RTG operations:

Access

Aggregation

Switch-1 Switch-2

Switch-3

(Pri) = Primary interface with preemption enabled

(Act) = Active interface currently forwarding traffic

ae0.0 is selected as the primary

interface for the rtg-1 RTG group


Lab 6: Implementing LAGs and RTG

Configure and monitor LAGs and RTG.






Virtual Chassis

Overview of Virtual Chassis



What Is It?

Two or more interconnected EX Series switches

operating as a single Virtual Chassis system

Valid chassis combinations

•Two or more (up to 10) EX4200s

•Two EX4500s

•Two EX4500s with up to eight EX4200s

•Two EX8200s including an external

routing engine

10 RU JunosUp to 10 switches can

be interconnected


Benefits of Virtual Chassis

Virtual Chassis benefits include:

•High availability: Redundant REs

• Enables the use of NSR

•Simplified network design: Single network entity to manage,

configure, and monitor; potential elimination of STP; flexible

placement of member switches

Junos

RE 0

RE 1

LC

LC

LC

LC

LC

LC

LC

LC


Virtual Chassis Components

Virtual Chassis components include:

•EX Series switches

• Participating switches serve as REs or line cards (LCs)

•Virtual Chassis ports (can be dedicated VCPs or uplink ports

converted to extended VCPs through configuration)

• VCPs interconnect PFEs from one switch to another to form a

single backplane

RE 0

Location 1 Location 2

Gigabit Ethernet or 10 GbE extended VCPs

(must be enabled through configuration)


Dedicated VCPs

(enabled by default)

LC

LC

LCLC

LC

LC

RE 1


Virtual Chassis Cabling Options (1 of 3)

Dedicated Virtual Chassis daisy-chained ring method

•Longest cable spans the entire Virtual Chassis; maximum

length between end systems is 5 meters

Note: The EX4200 Series switches come with a .5 meter cable.

You can acquire longer cables in lengths of 1, 3, and 5 meters.



Dedicated Virtual Chassis braided ring method

•Maximum length between end devices in a Virtual Chassis

consisting of 10 EX Series switch is 22.5 meters



Extended Virtual Chassis ring method

•Maximum circumference of ring using is 100 km; uses 1 GbE

or 10 GbE uplinks to extend the distance of the Virtual Chassis

Virtual Chassis Location 1 Virtual Chassis Location 2

GbE or 10 GbE uplink ports

GbE or 10 GbE uplink ports

Up to 100 km

This option is required when the circumference of a Virtual Chassis exceeds 22.5 meters.

This option is often used to interconnect wiring closets or data center racks or rows.

Dedicated Virtual

Chassis ports


RE placement recommendations:

•Ensure spatial redundancy and avoid split Virtual Chassis

issues and other failure conditions by evenly spacing the

master and backup REs (by hop) and by separating REs

from uplinks

Recommended RE Placement (1 of 2)

Uplink

Uplink

Dedicated Virtual Chassis daisy-chained ring Dedicated Virtual Chassis braided ring

RE 0

Uplink

Uplink

RE 1

RE 0

RE 1


RE placement recommendations (contd.):

•When implementing an extended Virtual Chassis, you should

place the master and backup REs in different locations

Recommended RE Placement (2 of 2)

Extended Virtual Chassis ring

RE 0

Location 1 Location 2



Dedicated VCPs

RE 1


Master and Backup Election

Mastership determination:1. Member with the highest user-configured priority

• Priority range is 1–255, factory-default value is 128

2. Member previously functioning as master prior to reboot

3. Member with the longest standing uptime• Difference must be greater than 1 minute

4. Member with the lowest MAC address• Used as tie breaker if all is equal through the first three

determination steps

5. Second member in election decision tree becomes backup

switch; all other members are line cards

Note: If a master or backup fails, one of the line card switches

is elected the new backup switch using the same criteria.


Member ID and Interface Names

All member switches are assigned a member ID (0–9)

•Member ID is assigned manually through configuration or

dynamically from the master switch (usually member ID 0)

•Member ID is preserved through reboots

•Member ID serves as slot number for interface naming

RE 0

RE 1

LC

LC

Member ID: 0

Member ID: 1

Member ID: 2

Member ID: 3


Replacing a Member Switch

When a member switch is removed, its member ID is

not automatically released and made available nor

will the replacement switch automatically inherit the

configuration associated with the previous switch

•Recommended replacement steps:

1. Recycle the member ID of the switch being replaced so it

becomes the next-lowest available unused member ID

2. Add replacement switch which should automatically be assigned

the recycled member ID and inherit the required configuration

{master:0}

user@Switch-1> request virtual-chassis recycle member-id <member-id>

Note: You recycle member IDs on the master switch.


Think About It!

Given the member ID assignments, what are the

interface names for the highlighted interfaces?

•Hint: All member switches are 48 port models and all

interfaces are Gigabit Ethernet interfaces

Location #2

Member ID: 0

Member ID: 1

Member ID: 2

Member ID: 3

RE 0

RE 1

LC

LC

ge-3/0/46 and ge-3/0/47ge-1/0/0 and ge-1/0/1


{master:0}[edit]

user@Switch-1# show interfaces vme

unit 0 {

family inet {

address 10.210.14.148/27;

}

}

{master:0}[edit]

user@Switch-1# run show interfaces terse vme

Interface Admin Link Proto Local Remote

vme up up

vme.0 up up inet 10.210.14.148/27

Management Connectivity (1 of 2)

Single management interface and IP address

•Individual management Ethernet ports (me0) on member

switches are tied to a special management VLAN associated

with a Layer 3 virtual management Ethernet (VME) interface

•The Virtual Chassis system is managed as a single network

element; therefore, it has only one management IP address

RE 0

RE 1

LC

LC


Management Connectivity (2 of 2)

Single virtual console

•Connection to a console on any member switch in a Virtual

Chassis system is redirected to the master switch by the

virtual console software running on all member switches

RE 0

RE 1

LC

LC

Console ports


Software Upgrades

You can perform software upgrades for a single Virtual Chassis member or for all members from the master switch

Master switch performs a software compatibility check for each member added to the Virtual Chassis

•If a version mismatch exists, a syslog message is generated and the newly added switch is placed in an inactive state

•Upgrade incompatible switches from the master switch manually or enable the automatic software upgrade option

{master:0}

user@Switch-1> request system software add member ?

Possible completions:

<member> Install package on VC Member (0..9)


Topology Discovery (1 of 3)

Virtual Chassis members use VCCP to create a loop-

free topology

•LSA-based discovery messages are exchanged between all

PFEs and build the member switch and PFE topology maps

•Each switch runs the shortest-path first (SPF) algorithm for

each PFE which creates PFE map tables between all PFEs

•Each PFE builds source ID egress filter tables used to

prevent broadcast and multicast packets from looping

b ca e fd h ig


Virtual Chassis cables and backplane

VCCP LSA-based messages

PFEs



Topology discovery example:

b ca e fd h ig

Physical Virtual Chassis Cabling

a

i

b

h

d

f

e

c

g

Virtual Chassis Backplane

Logical Virtual Chassis Ring Topology

Note: a, b, c, … i are PFEs



Topology discovery example (contd.):

a

i

b

h

d

f

e

c

g

Logical Virtual Chassis Ring Topology

Virtual Chassis Backplane

Note: a, b, c, … i are PFEs

a

b

i

c

h

d

g

e

f

PFE a’s Rooted Reachability SPF Tree

g

f

h

e

i

d

a

c

b

PFE g’s Rooted Reachability SPF Tree


Inter-Chassis Packet Flow

Packets always take the shortest path through a Virtual Chassis

•Shortest path is determined by hop count and bandwidth

•Inter-chassis packet flow examples:

1. Packets going from ge-0/0/10 to ge-3/0/14 pass through member 4 because it is a shorter path

2. Packets going from ge-0/0/28 to ge-2/0/47 pass through member 1 because it is a shorter path

0

1

2

3

4

ge-0/0/10

ge-3/0/14

ge-0/0/28

ge-2/0/47






Virtual Chassis


Configuring and Monitoring a Virtual Chassis


Virtual Chassis Configuration

You enable Virtual Chassis configuration options under

the [edit virtual-chassis] hierarchy:{master:0}[edit virtual-chassis]

user@Switch-1# set ?


+ apply-groups Groups from which to inherit configuration data

+ apply-groups-except Don't inherit configuration data from these groups

> auto-sw-update Auto software update

> fast-failover Fast failover mechanism

id Virtual Chassis identifier, of type ISO system-id

> mac-persistence-timer How long to retain MAC address when member leaves Virtual Chassis

> member Member of Virtual Chassis configuration

no-split-detection Disable split detection. Only recommended in a 2 member setup

preprovisioned Only accept preprovisioned members

> traceoptions Global tracing options for Virtual Chassis


user@Switch-1# set redundancy graceful-switchover?


> graceful-switchover Enable graceful switchover on supported hardware

•To minimize traffic interruption during an RE failover scenario,

enable graceful Routing Engine switchover:


Dynamic configuration steps:

Dynamic Configuration Process (1 of 2)

1. Install desired master switch:

• Power up desired master switch,

switch becomes master and obtains

member ID 0, assign mastership

priority 255

2. Add desired backup switch:

• Connect to master switch using

Virtual Chassis cable, power up

desired backup switch, switch is

elected as backup and dynamically

assigned member ID 1, assign

mastership priority 255

0

1

2

3

4

Linecard

Backup (Backup RE)

Master (Active RE)

Linecard

Linecard

ON

ON

{master:0}[edit virtual-chassis]

user@Switch-1# set member <member-id> mastership-priority <priority>


Dynamic configuration steps (contd.):

Dynamic Configuration Process (2 of 2)

3. Add line card switch:

• Connect to switch above with VCB

cable, power up third switch—switch

becomes line card and is dynamically

assigned member ID 2, assign desired

mastership priority

4. Repeat Step 3 to add subsequent

line card switches:

• Last line card switch completes loop

by connecting with master

0

1

2

3

4

Linecard

Backup (Backup RE)

Master (Active RE)

Linecard

Linecard

ON

ON

ON

ON

ON


user@Switch-1# set member <member-id> mastership-priority <priority>


Preprovisioned Configuration Example


user@Switch-1# show

preprovisioned;

member 0 {

role routing-engine;

serial-number BM0208105168;

}

member 1 {

role line-card;


}

member 2 {



}

member 3 {

role line-card;


}

Member ID: 0

Member ID: 1

Member ID: 2

Member ID: 3

RE 0

RE 1

LC

LC

Note: You should power on the switch designated as RE0 first, create and activate

the desired preprovisioned configuration, and then add the remaining switches.

Note when preprovisioned option is used, you do not specify a

mastership priority but rather only assign the role to a given device.


Monitoring Virtual Chassis Operations

Use the show virtual-chassis commands to

monitor Virtual Chassis operations:{master:0}

user@Switch-1> show virtual-chassis ?


<[Enter]> Execute this command

active-topology Virtual Chassis active topology

device-topology PFE device topology

fast-failover Fast failover status

login

protocol Show Virtual Chassis protocol information

status Virtual Chassis information

vc-path Show virtual-chassis packet path

vc-port Virtual Chassis port information

| Pipe through a command


Verifying Virtual Chassis Port State

Use show virtual-chassis vc-port to view

VCP state and details:{master:0}

user@Switch-1> show virtual-chassis vc-port

fpc0:

--------------------------------------------------------------------------

Interface Type Trunk Status Speed Neighbor

or ID (mbps) ID Interface

PIC / Port

vcp-0 Dedicated 2 Up 32000 1 vcp-0


fpc1:

--------------------------------------------------------------------------



PIC / Port




Enabling and Disabling Virtual Chassis

Ports

Built-in VCPs (vcp-0/vcp-1) are enabled by default

•You can disable or re-enable VCPs in operational mode:

{master:0} VC

user@Switch-1> request virtual-chassis vc-port set interface vcp-0 disable

{master:0}


fpc0:

--------------------------------------------------------------------------



PIC / Port

vcp-0 Dedicated 2 Disabled 32000


...

{master:0}

user@Switch-1> request virtual-chassis vc-port set interface vcp-0

{master:0}


fpc0:

--------------------------------------------------------------------------



PIC / Port

vcp-0 Dedicated 2 Down 32000


...


Verifying Status Information

Use show virtual-chassis status to view

Virtual Chassis status information:{master:0}

user@Switch-1> show configuration virtual-chassis

preprovisioned;

member 0 {



}

member 1 {

role line-card;


}

{master:0}

user@Switch-1> show virtual-chassis status

Preprovisioned Virtual Chassis

Virtual Chassis ID: 8d5c.a77f.8de8

Mastership Neighbor List

Member ID Status Serial No Model priority Role ID Interface

0 (FPC 0) Prsnt BM0208105168 ex4200-24t 129 Master* 1 vcp-0

1 vcp-1

1 (FPC 1) Prsnt BM0208124231 ex4200-24t 0 Linecard 0 vcp-0

0 vcp-1

Member ID: 0

Member ID: 1

RE 0

LC


Summary

In this chapter, we:

•Listed and described features that promote high availability

•Configured and monitored high availability features

•Described key concepts and components of a Virtual

Chassis

•Explained the operational details of a Virtual Chassis

•Implemented a Virtual Chassis and verified its operations


Review Questions

1. What is the purpose of LACP?

2. In what situation would you likely find RTG?

3. List some benefits of implementing a Virtual

Chassis.


Lab 7: Virtual Chassis

Implement and verify operations of a Virtual Chassis.

Worldwide Education Services

junos enterprise switchingluk.kis.p.lodz.pl/ksbg/wyklad/v2017/03 vc lag - jex_11.a... · 2015. 10....

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