PLNOG 13: Marek Janik: Rings in Ethernet Networks

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com/enterprise

Pierścienie w sieciach Ethernet

Marek Janik

[email protected]

mailto:[email protected]

Agenda

Po co właściwie są protokoły pierścieniowe

RRPP/SEP – protokoły własne Huawei

G.8032/ERPS – ITU

Założenia

Porównanie ERPSv1 i ERPSv2

Topologie

Konfiguracje praktyczne

Drawbacks of STP – The convergence time is too long!

STP (spanning-tree protocol) is built for the redundant links and loop avoidance network.

When topology changes, STP takes about 30-50 seconds to converge.

RSTP (Rapid STP) improves the speed of convergence for bridged network from 30-50

seconds to about 4 seconds, by immediately transitioning root and designated ports to

the forwarding state.

Ring Protocols only spends 50-200 ms converging but it uses a ring topology instead of

tree topology.

Potrzeby wynikające z ograniczeń STP

STP RSTP Ring Proto

Topology Type Any Topology Any Topology Ring Topology

Convergence Time 30-50 seconds 6 seconds 50-250ms*

Company Cisco 3 COM Foundry HP Extreme Huawei Huawei

Protocol REP RRPP MRP/

MRPII

RRPP EAPS

EAPSv2

RRPP SEP

Name Resilient

Ethernet

Protocol

Rapid

Ring

Protection

Protocol

Metro

Ring

Protocol

Rapid

Ring

Protection

Protocol

Ethernet

Automatic

Protection

Switching

Rapid

Ring

Protection

Protocol

Smart

Ethernet

Protection

Ring

Topologies

Single ring/

More

complex

rings

Single ring/

Two or more

rings

Single ring/

Overlappin

g rings

Single ring/

Two or more

rings

Single

rings/More

complex

rings

Single ring/

Two or more

rings

Single

ring/More

Complex

rings/Multi

Rings

Convergence

Time

50-250ms < 200ms 50ms < 200ms Faster

than

RSTP

50-60ms 50-60ms

Porównanie protokołów „pierścieniowych”

Principle of RRPP---Disadvantage

RRPP meets the requirement for fast protection but

encounters the following problems due to limitations of its

basic mechanism:

Sub-rings must be directly connected to the major ring and a major ring

can have only one level of sub-rings.

RRPP cannot be used with STP, RSTP, or MSTP properly.

The revertive switching function cannot be disabled.

The logical topology cannot be displayed, which makes network

maintenance difficult.

The configuration is complex especially when there are multiple rings on

the network.

Page 6

Single Ring

Only one ring exists on the network. At this time, you need to define only an

RRPP domain and an RRPP ring. In this networking, the change of the

topology can be detected rapidly and the convergence time is short.

Page 7

Intersectant Ring

There are two or more than two rings on the network. There are two

common nodes between rings. Only an RRPP domain needs to be defined.

One ring is specified as the major ring, and the other rings are sub-rings.

Page 8

Tangent Ring

There are two or more than two rings on the network. There is one

common node between rings. Each ring must belong to a different RRPP

domain. This topology can be adopted when the network is of a large scale

and the area-based management is required.

Page 9

Principle of SEP---Feature

SEP is designed to implement failover within 50 ms on ring

networks and provide the following functions:

Support more complex ring networks.

Work with STP, RSTP, or MSTP.

Prevent traffic from being switched back after link recovery, which

improves network stability.

Support logical topology display to improve network maintainability.

Simplify configuration on multi-ring networks.

Support flexible selection of the blocked point to better implements

traffic load balancing.

Page 10

Open ring: It is a chain topology. An open ring is also called a segment, and

each segment has a unique ID.

Closed ring: It can be considered as a special open ring where two edge ports

are located on the same node.

A SEP basic topology must have a blocked point at any time.

Principle of SEP---Basic Topology

Open

ring Closed

Ring

Page 11

Closed rings and open rings can form a complex topology.

The basic topologies can transmit topology change notifications to each other,

and no complex configurations are required.

Principle of SEP---Complex Topology

SEP Network Architecture

Konfiguracja SEP – Single-Ring krok 1 <HUAWEI> system-view

[HUAWEI] sysname LSW1

[LSW1] sep segment 1

[LSW1-sep-segment1] control-vlan 10

[LSW1-sep-segment1] protected-instance all

[LSW1-sep-segment1] quit

<HUAWEI> system-view
























Konfiguracja SEP – Single-Ring krok 2 LSW1] interface gigabitethernet 0/0/1

[LSW1-GigabitEthernet0/0/1] port link-type hybrid

[LSW1-GigabitEthernet0/0/1] stp disable

[LSW1-GigabitEthernet0/0/1] sep segment 1 edge primary

[LSW1-GigabitEthernet0/0/1] quit

[LSW1] interface gigabitethernet 0/0/3



[LSW1-GigabitEthernet0/0/3] sep segment 1 edge secondary





[LSW2-GigabitEthernet0/0/1] sep segment 1

[LSW2-GigabitEthernet0/0/1] quit[

LSW2] interface gigabitethernet 0/0/2









[LSW3-GigabitEthernet0/0/1] quit[

LSW3] interface gigabitethernet 0/0/2




Konfiguracja SEP – Single-Ring krok 3


[LSW1-sep-segment1] block port optimal

#Set the priority of GE0/0/2 on LSW3.


[LSW3-GigabitEthernet0/0/2] sep segment 1 priority 128


Page 16

Ring Network

Protocol Advantage Disadvantage

STP/RSTP/MSTP •Apply to all Layer 2 networks.

•Are standard IEEE protocols that allow Huawei

devices to communicate with non-Huawei devices.

Provides a low convergence speed on a large network,

which cannot meet the carrier-class reliability requirement.

RRPP Features fast convergence, meeting the carrier-class

reliability requirement.

•Supports only level-1 subrings on ring networks.

•Is a Huawei proprietary protocol that does not support

interoperability between Huawei and non-Huawei devices.

SEP

•Applies to all Layer 2 networks.

•Features fast convergence, meeting the carrier-

class reliability requirement.

•Displays the topology of an entire ring, facilitating

fault location and device maintenance.

Is a Huawei proprietary protocol that does not support

interoperability between Huawei and non-Huawei devices.

ERPS Features fast convergence, meeting the carrier-class

reliability requirement. Supports single-ring and multi-ring networking.

Introduction to ERPS

On a ring network, devices supporting ERPS can communicate with each other regardless of their

manufacturers.

ERPS is a protocol defined by the ITU-T to prevent loops at Layer 2. Because it is defined in Recommendation ITU-T

G.8032/Y.1344, it is also called G.8032. ERPS defines R-APS PDUs and the protection switching mechanism.

ERPS blocks a specified port to prevent loops at the Ethernet link layer.

ERPS has two versions: ERPSv1 released in June 2008 and ERPSv2 released in August 2010.

Comparison Among Ring Network Protocols Supported by Huawei Devices

17

G.8032 Objectives and Principles Use of standard 802 MAC and OAM frames around the ring. Uses standard

802.1Q (and amended Q bridges), but with xSTP disabled.

Ring nodes supports standard FDB MAC learning, forwarding, flush

behaviour and port blocking/unblocking mechanisms.

Prevents loops within the ring by blocking one of the links (either a pre-

determined link or a failed link).

Monitoring of the ETH layer for discovery and identification of Signal Failure

(SF) conditions.

Protection and recovery switching within 50 ms for typical rings.

Total communication for the protection mechanism should consume a very

small percentage of total available bandwidth.

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 18

G.8032 Terms and Concepts

Ring Protection Link (RPL) – Link designated by mechanism that is blocked during

Idle state to prevent loop on Bridged ring

RPL Owner – Node connected to RPL that blocks traffic on RPL during Idle state and

unblocks during Protected state

Link Monitoring – Links of ring are monitored using standard ETH CC OAM messages

(CFM)

Signal Fail (SF) – Signal Fail is declared when ETH trail signal fail condition is detected

No Request (NR) – No Request is declared when there are no outstanding conditions

(e.g., SF, etc.) on the node

Ring APS (R-APS) Messages – Protocol messages defined in Y.1731 and G.8032

Automatic Protection Switching (APS) Channel - Ring-wide VLAN used exclusively

for transmission of OAM messages including R-APS messages

Page 19

Basic ERPS Concepts

Control VLAN: A control VLAN is only used to transmit R-APS PDUs. Each ERPS ring must

have a control VLAN. After a port is added to an ERPS ring that has a control VLAN, the port is

automatically added to the control VLAN. ERPS rings must use different control VLANs.

Data VLAN: A data VLAN is used to transmit data packets.

Protected instance: On an ERPS-enabled Layer 2 device, VLANs that transmit R-APS PDUs

and data packets must be mapped to a protected instance so that ERPS forwards or blocks

these VLAN packets. Otherwise, VLAN packets may cause broadcast storms on the ring network,

making the network unavailable.

Example

As shown in the figure, four switches form an ERPS ring

and are nodes on the ring.

The port marked in red is the RPL owner port. When ERPS

works normally, the RPL owner port is in Discarding state,

preventing loops on the ERPS ring.

Physical topology has all nodes connected in

a ring

ERP guarantees lack of loop by blocking the

RPL (link between 6 & 1 in figure)

Logical topology has all nodes connected

without a loop.

Each link is monitored by its two adjacent

nodes using ETH CC OAM messages

Signal Failure as defined in Y.1731, is trigger

to ring protection

Loss of Continuity

Server layer failure (e.g. Phy Link Down)

RPL

Owner RPL

ETH-CC

ETH-CC

ETH-CC

ETH-CC

ETH-CC

ETH-CC

ETH-CC

ETH-CC

ETH

-CC

ETH

-CC

ETH

-CC

ETH

-CC

Physical topology

Logical topology

1 2 6

4 3 5

RPL

1 2 6

4 3 5

Ring Idle State

Protection Switching Link Failure

A. Link/node failure is detected by the

nodes adjacent to the failure.

B. The nodes adjacent to the failure,

block the failed link and report this

failure to the ring using R-APS (SF)

message

C. R-APS (SF) message triggers

RPL Owner unblocks the RPL

All nodes perform FDB flushing

D. Ring is in protection state

E. All nodes remain connected in the

logical topology.

Physical topology

Logical topology

1 2 6

4 3 5

RPL 1 2 6

4 3 5

RPL

1 2 6

4 3 5

1 2 6

4 3 5

RPL

Owner RPL

R-APS(SF) R-APS(SF)

R-APS(SF)

R-A

PS(S

F)

Protection Switching Failure Recovery

A. When the failed link recovers, the

traffic is kept blocked on the nodes

adjacent to the recovered link

B. The nodes adjacent to the recovered

link transmit R-APS(NR) message

indicating they have no local request

present

C. When the RPL Owner receives R-

APS(NR) message it Starts WTR timer

D. Once WTR timer expires, RPL Owner

blocks RPL and transmits R-APS (NR,

RB) message

E. Nodes receiving the message –

perform a FDB Flush and unblock

their previously blocked ports

F. Ring is now returned to Idle state

RPL

Owner RPL

R-APS(NR) R-APS(NR)

R-APS(NR)

R-A

PS(N

R)

R-APS(NR, RB)

R-A

PS(N

R, R

B)

Physical topology

Logical topology

1 2 6

4 3 5

RPL

1 2 6

4 3 5

1 2 6

4 3 5

RPL

1 2 6

4 3 5

Porównanie ERPSv1 i ERPSv2 Function ERPSv1 ERPSv2

Ring type Supports single rings only.

Supports single rings and

multi-rings. A multi-ring

topology comprises major

rings and sub-rings.

Port role configuration Supports the ring protection link

(RPL) owner port and ordinary ports.

Supports the RPL owner

port, RPL neighbor port,

and ordinary ports.

Topology change

notification Not supported. Supported.

R-APS PDU

transmission modes on

sub-rings

Not supported. Supported.

Revertive and non-

revertive switching

Supports revertive switching by

default and does not support non-

revertive switching or switching

mode configuration.

Supported.

Manual port blocking Not supported.

Supports forced switch

(FS) and manual switch

(MS).

Interconnected rings with a VC or NVC

Page 24

VC: RAPS PDUs in sub-rings are

transmitted to the major ring

through interconnected nodes. The

RPL owner port of the sub-ring

blocks both RAPS PDUs and data

traffic.

NVC: RAPS PDUs in sub-rings are

terminated on the interconnected

nodes. The RPL owner port blocks

data traffic but not RAPS PDUs in

each sub-ring.

Topologie ERPS – Single-Ring, Multi-

Instance

Topologie ERPS – Multi-Ring and Ladder

LSW4LSW1

LSW3

Blocked port

LSW2

LSW6 LSW5

Ring 2

Ring 1

LSW5LSW5

VLAN/VPLS

NPE

Ring 3

Konfiguracja ERPS – Single Ring # Configure SwitchA.

The configurations of SwitchB, SwitchC, SwitchD, and SwitchE are similar to the

configuration of SwitchA

<Switch> system-view

[Switch] sysname SwitchA

[SwitchA] vlan batch 100 to 200

[SwitchA] interface gigabitethernet 1/0/1

[SwitchA-GigabitEthernet1/0/1] port link-type trunk

[SwitchA-GigabitEthernet1/0/1] port trunk allow-pass vlan 100 to 200

[SwitchA-GigabitEthernet1/0/1] quit



[SwitchA-GigabitEthernet1/0/2] port trunk allow-pass vlan 100 to 200


# Configure SwitchA.

[SwitchA] erps ring 1

[SwitchA-erps-ring1] control-vlan 10

[SwitchA-erps-ring1] protected-instance 1

[SwitchA-erps-ring1] quit

[SwitchA] stp region-configuration

[SwitchA-mst-region] instance 1 vlan 10 100 to 200

[SwitchA-mst-region] active region-configuration

[SwitchA-mst-region] quit

Konfiguracja ERPS – Single Ring # Configure SwitchA.


[SwitchA-GigabitEthernet1/0/1] stp disable

[SwitchA-GigabitEthernet1/0/1] erps ring 1






# The configurations of SwitchB, SwitchD, and SwitchE are similar to the

configuration of SwitchA,

# Configure SwitchC.

[SwitchC] interface gigabitethernet 1/0/1

[SwitchC-GigabitEthernet1/0/1] stp disable

[SwitchC-GigabitEthernet1/0/1] erps ring 1

[SwitchC-GigabitEthernet1/0/1] quit



[SwitchC-GigabitEthernet1/0/2] erps ring 1 rpl owner


[SwitchC] display erps ring 1 verbose

Ring ID : 1

Description : Ring 1

Control Vlan : 10

Protected Instance : 1

WTR Timer Setting (min) : 6 Running (s) : 0

Guard Timer Setting (csec) : 100 Running (csec) : 0

Holdoff Timer Setting (deciseconds) : 0 Running (deciseconds) : 0

Ring State : Idle

RAPS_MEL : 7

Time since last topology change : 0 days 0h:33m:4s

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

Port Port Role Port Status Signal Status

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

GE1/0/1 Common Forwarding Non-failed

GE1/0/2 RPL Owner Discarding Non-failed

Konfiguracja ERPS – Multi-Ring krok 1


[HUAWEI] sysname SwitchA











[HUAWEI] sysname SwitchD

[SwitchD] interface gigabitethernet 0/0/1

[SwitchD-GigabitEthernet0/0/1] port link-type trunk

[SwitchD-GigabitEthernet0/0/1] quit









[HUAWEI] sysname SwitchB

[SwitchB] interface gigabitethernet 0/0/1

[SwitchB-GigabitEthernet0/0/1] port link-type trunk

[SwitchB-GigabitEthernet0/0/1] quit





[HUAWEI] sysname SwitchC


[SwitchC-GigabitEthernet0/0/1] port link-type trunk





Konfiguracja ERPS – Multi-Ring krok 2 [SwitchA] erps ring 1
















[SwitchB] erps ring 1

[SwitchB-erps-ring1] control-vlan 10

[SwitchB-erps-ring1] protected-instance 1

[SwitchB-erps-ring1] quit

[SwitchB] stp region-configuration

[SwitchB-mst-region] instance 1 vlan 10 100 to 200

[SwitchB-mst-region] active region-configuration

[SwitchB-mst-region] quit

Konfiguracja ERPS – Multi-Ring krok 2 [SwitchD] erps ring 1

[SwitchD-erps-ring1] control-vlan 10

[SwitchD-erps-ring1] protected-instance 1

[SwitchD-erps-ring1] quit

[SwitchD] stp region-configuration

[SwitchD-mst-region] instance 1 vlan 10 100 to 200

[SwitchD-mst-region] active region-configuration

[SwitchD-mst-region] quit

[SwitchD] erps ring 2








[SwitchC] erps ring 2

[SwitchC-erps-ring2] control-vlan 20

[SwitchC-erps-ring2] protected-instance 2

[SwitchC-erps-ring2] quit

[SwitchC] stp region-configuration

[SwitchC-mst-region] instance 2 vlan 20 300 to 400

[SwitchC-mst-region] active region-configuration

[SwitchC-mst-region] quit

Konfiguracja ERPS – Multi-Ring krok 3 [SwitchA] erps ring 1

[SwitchA-erps-ring1] version v2



[SwitchA-erps-ring2] version v2

[SwitchA-erps-ring2] sub-ring



[SwitchB-erps-ring1] version v2



[SwitchC-erps-ring2] version v2

[SwitchC-erps-ring2] sub-ring



[SwitchD-erps-ring1] version v2



[SwitchD-erps-ring2] version v2

[SwitchD-erps-ring2] sub-ring


Konfiguracja ERPS – Multi-Ring krok 4 [SwitchA] interface gigabitethernet 0/0/1












[SwitchA-GigabitEthernet0/0/3] quit#


[SwitchB-GigabitEthernet0/0/1] stp disable

[SwitchB-GigabitEthernet0/0/1] erps ring 1 rpl owner




[SwitchB-GigabitEthernet0/0/2] erps ring 1


Konfiguracja ERPS – Multi-Ring krok 4 [SwitchC] interface gigabitethernet 0/0/1


[SwitchC-GigabitEthernet0/0/1] erps ring 2 rpl owner





[SwitchC-GigabitEthernet0/0/2] quit#


[SwitchD-GigabitEthernet0/0/1] stp disable

[SwitchD-GigabitEthernet0/0/1] erps ring 1













[SwitchA-erps-ring2] tc-notify erps ring 1



[SwitchD-erps-ring2] tc-notify erps ring 1


Konfiguracja ERPS – Multi-Instance krok 1 <HUAWEI> system-view

[HUAWEI] sysname SwitchA








[HUAWEI] sysname SwitchB








[HUAWEI] sysname SwitchC








[HUAWEI] sysname SwitchD







Konfiguracja ERPS – Multi-Instance krok 2 [SwitchA] erps ring 1
































Konfiguracja ERPS – Multi-Instance krok 2 [SwitchC] erps ring 1
































Konfiguracja ERPS – Multi-Instance krok 3




[SwitchA-GigabitEthernet0/0/1] erps ring 2 rpl owner














[SwitchB-GigabitEthernet0/0/2] erps ring 1 rpl owner



Konfiguracja ERPS – Multi-Instance krok 3





















Thank you www.huawei.com

Internet

PLNOG 13: Marek Janik: Rings in Ethernet Networks