introduction to wan switching presented by drew spesard, internetwork experts (ccie #1495) &...

Introductionto

WAN Switching

presented byDrew Spesard, Internetwork Experts (CCIE #1495)

&Roland Gonzalez, Internetwork Experts (CCIE #2088)

What is WAN Switching?

•“WAN switching” is the process of forwarding traffic across the WAN based on the predefined destination of the data. Switching operates at the data link layer of the OSI model.

•Specifically, WAN switching uses the concepts of cell relay technology to statistically multiplex all network traffic (voice, video, and data) across WAN “trunks” without predefined timeslots for each connection type.

•Cell relay networks use small, fixed-length packets, called cells, that contain address and control information in a header and the user's payload. The use of a common cell format for the encapsulation and transport of all network traffic, voice, video, and data results in simplified routing and multiplexing.

•Cell relay networks are characterized by very high throughput, short delays, and very low error rates.

TDM combines the information from different sources onto a single serial transmission, and each source has a predefined timeslot on the multiplexed line. If a source has nothing to send, then the timeslot goes unused, and the bandwidth is “wasted”.

Fixed-length Cell Relay Statistical Multiplexing

…uses switching and multiplexing technique in which user voice, video, and data is placed into fixed-length cells that are routed to their destination without regard to content.

ATM Cell Relay Networks

One of the primary benefits of ATM networks is the traffic management that establishes how a particular connection is specified and the resources required to support the connection through the network. It can provide users with a guaranteed QoS.

The current classes of QoS as defined by the ATM Forum are:

•Constant Bit Rate (CBR)•Variable Bit Rate (VBR)•Unspecified Bit Rate (UBR)•Available Bit Rate (ABR)


• Constant bit rate (CBR)— typically used to carry constant rate traffic with a fixed timing relationship. CBR is typically for circuit emulation supporting uncompressed voice and

videoconferencing communication. • Variable bit rate (VBR)—VBR service can be broken into

two groups: VBR-RT - Real-time VBR is used for connections that carry VBR traffic in which

there is a fixed timing relationship between samples (e.g. variable bit rate video or voice compression).

VBR-NRT - Nonreal-time VBR is used for connections that carry VBR traffic in which there is no timing relationship between data samples, but a guarantee of QoS (on bandwidth or latency) is still required (e.g. Frame Relay internetworking, in which the CIR of the Frame Relay connection is mapped

into a bandwidth guarantee within the ATM network).


• Unspecified Bit Rate (UBR)— does not offer any service guarantees. UBR is typically for for the bursty, unpredictable traffic from LAN protocols served by ATM routers.

• Available Bit Rate (ABR)— supports variable rate data transmissions and does not preserve any timing relationships between source and destination. The network provides a best effort service above a specified

Minimum Cell Rate (MCR).

Cisco WAN Switching Products

•BPX 8600 series wide area switches (8620, 8650, 8680)

•IGX 8400 series wide area switches (8410, 8420, 8430)

•MGX 8220 edge concentrator

•MGX 8800 wide area edge switch


•BPX 8620 broadband edge switch

• Broadband ATM switch that is designed to provide edge switching into a high-speed core.

• Supports ATM interfaces from E3 speed (34Mb) to OC12 (622Mb).

• Provides 20Gb of switching throughput


•BPX 8620 broadband edge switch

• provides ATM-based broadband services and integrates the Cisco IOS® software platform to deliver IP services (while still supporting frame relay, ATM, and leased line services).

• combines layer 3 routing intelligence with Layer 2 ATM capabilities (QOS, buffering, & queuing) via Multiprotocol Label Switching (MPLS).

• Allows for provisioning of integrated IP+ATM services (VIP, VPNs, Web Hosting)


•BPX 8650 IP+ATM wide area switch

• Combines BPX 8620 platform with Cisco 7204 router shelf

• Provides ATM-based broadband services and integrates the Cisco IOS® software platform to deliver IP services (while still supporting frame relay, ATM, and leased line services).

• Combines layer 3 routing intelligence with Layer 2 ATM capabilities (QOS, buffering, & queuing) via Multiprotocol Label Switching (MPLS).

• Allows for provisioning of integrated IP+ATM services (VIP, VPNs, Web Hosting)


•BPX 8680 Universal Service Node

• Combines BPX 8620 with MGX 8850 platform

• Designed for very large installations (up to 16000 DS1s).

• Supports IP+ATM for broadband and narrowband circuits.

• Scales to OC48 (2.4Gb) interface speeds


•IGX 8400 series wide area switch (8410, 8420, 8430)

• Available in 8, 16, & 32 slot chassis

• Supports narrowband and broadband connections (up to OC3)

• Supports wide range of services including digital voice (CAS/CCS), frame relay, legacy data (SNA BISYNC, V.35, etc.) and ATM UNI or NNI.

• Less switching throughput than the BPX switch (1.2 GB)

• Used in enterprise networks for combining multiple services across the WAN.


•MGX 8220 edge concentrator

• Concentrates narrowband traffic for backbone ATM switches.

• Supports up to 80 T1/E1 interfaces.

• Uses ATM Adaption Layers to adapt narrowband services (frame relay, circuit emulation) to ATM service.

• As of OS version 4.1, MGX 8220 can act as a stand alone unit that connects via ATM UNI/NNI to router or ATM switch (and not just the BPX 8620). Generally, this platform does not perform any routing/switching decisions.


• MGX 8800 wide area edge switch

• New product that can act as stand alone switch or as an access shelf for a BPX 8600.

• Currently has 1.2Gb switching fabric, but a 45Gb switching fabric will be available soon.

• Provides IP+ATM services, as well as frame relay, circuit emulation, SNA outsourcing, voice over IP.

• Interface speeds range from DS0 (64Kbs) to OC48 (2.4Gb).

• Supports 24 single-height cards; up to 1400 DS1s

Typical WAN Architecture

WAN Architecture

Cisco WAN Switched Architecture consists of three types of nodes:

Routing Nodes (BPX switches) - make actual switching decisions and forward packets to appropriate trunk connections to other nodes.

Feeder Nodes (MGX 8220 concentrator shelves) - aggregate narrowband UNI connections and forward all traffic on a single trunk connection to a routing node.

Hybrid Nodes (IGX switches, MGX 8800 switches) - can aggregate “UNI connections” and route/switch packets to trunk connections that lead to ultimate destination.

Configuring the BPX 8600

There are four methods to access the BPX Command Line Interface:

Control Port: VT100 terminal emulation

Auxilary Port: VT100 terminal emulation

LAN Port: Telnet

IP Relay: Telnet


General Command Syntax:command <required parameter> … <optional parameter>

Commands have different privilege levels that correspond to the following user levels:

• Levels 1 through 6 (1 has more privilege)• SuperUser (level 0)• Service• StrataCom


Important commands:

help -or- ? Displays online help

<Escape> Enter Menu Driven Command Mode

. Display last 12 commandsbye Log outadduser Add a new user to the database

dspcds Display Cardsdsptrks Display Trunksdsplns Display Lines

Configuring the BPX 8600bpx1 TN SuperUser BPX 8600 9.1.10 Nov. 2 1999 13:34 CDT

NodeName Alarm Trunkbpx1 MAJOR

Last Command: cnfname bpx1

Next Command:

MAJOR ALARM


NodeName Alarm Trunkbpx1 MAJOR

This Command: cnfdate 1999 11 2 13 36 0

Warning: Changing time affects Cisco StrataView Plus statistics timestamps


Last Command: clrscrn

Next Command:


FrontCard BackCard FrontCard BackCard Type Rev Type Rev Status Type Rev Type Rev Status1 Empty 9 BXM-155 BDW SM-4 BA Active2 Empty 10 BXM-155 BDW SM-4 BA Standby3 ASI-T3 CFD T3-2 BE Active 11 Empty4 BXM-155 CJD MM-4 BB Active 12 Empty5 BXM-T3 DJB TE3-12BA Active 13 Empty6 Empty 14 Empty7 BCC-3 CMM LM-2 AC Active 15 ASM ACC LMASM AC Active8 BCC-3 CLM LM-2 AC Standby

Last Command: dspcds

Next Command:

MAJOR ALARM


Detailed Card Display for BXM-T3 in slot 5Status: ActiveRevision: DJBSerial Number: 881473Fab Number: 28-2218-02Queue Size: 228300Support: FST, 12 Pts,T3,VcShpngChnls:16320,PG[1]:16320PG[1]:1,2,3,4,5,6,7,8,9,10,11,12,Backcard Installed Type: LM-BXM Revision: BA Serial Number: 918976 Supports: 12 Pts, T3/E3

Last Command: dspcd 5

Next Command:


Detailed Card Display for BCC-3 in slot 7Status: ActiveRevision: CMM Backcard InstalledSerial Number: 518340 Type: LM-2Hardware Etch: B Revision: ACFab Number: 217702-00 Serial Number: 518675RAM Id: 9.1.10ROM Id: 9.1.10BOOT Id: H.C.MBRAM Id: 9.1.10RAM Size: 32 MegFlash EEPROMs: Standard - 4 MegSar Revision: CMUUp Revision: CM15

Last Command: dspcd 7

Next Command:

MAJOR ALARM


Adding a Trunk:

Enable the card/port as a trunk with the following command:

uptrk 9.1…the uptrk command is issued at both BPX switches at each end of the trunk

Configure the trunk: cnftrk 9.1

…for changing default values

Activate the trunk: addtrk 9.1

…issued at only one end of the connection.


TRK Type Current Line Alarm Status Other End 9.1 OC3 Clear - OK Axis1(AXIS)

Last Command: dsptrks

Next Command:

MAJOR ALARM


TRK 9.1 Config OC3 [96000 cps] BXM slot: 9Transmit Rate: 353208 Line framing: STS-3CSubrate data rate: -- coding: --Line DS-0 map: -- CRC: --Statistical Reserve: 1000 cps recv impedance: --Idle code: 7F hex cable type: --Max Channels/Port: 256 length: --Connection Channels: 256 Pass sync: YesTraffic: V,TS,NTS,FR,FST,CBR,VBR,ABR Loop clock: NoSVC Vpi Min: 0 HCS Masking: YesSVC Channels: 0 Payload Scramble: YesSVC Bandwidth: 0 cps Frame Scramble: YesRestrict CC traffic: No Virtual Trunk Type: --Link type: Terrestrial Virtual Trunk VPI: --Routing Cost: 10 Deroute delay time: 0 seconds

This Command: cnftrk 9.1

Stat Reserve (1000):


Adding a Line:

Enable the card/port as a line with the following command:

upln 4.1…the upln command is used for UNI connections to CPE

Configure the line: cnfln 4.1

…for changing default values


Line Type Current Line Alarm Status 3.1 T3 Major - Loss of Sig (RED) 3.2 T3 Major - Loss of Sig (RED) 4.1 OC3 Clear - OK 4.2 OC3 Clear - OK 5.1 T3 Clear - OK

Last Command: dsplns

Next Command:

MAJOR ALARM


LN 4.1 Config OC3 [353208cps] BXM slot: 4Loop clock: No Idle code: 7F hex

Line framing: -- coding: -- CRC: -- recv impedance: -- E1 signalling: -- encoding: -- cable type: -- T1 signalling: -- length: -- HCS Masking: Yes Payload Scramble: Yes 56KBS Bit Pos: -- Frame Scramble: Yes pct fast modem: -- Cell Framing: STS-3C

This Command: cnfln 4.1

Loop clock (N):


Adding an ATM PVC:

Enable the port with the following command:

upport 4.1 cnfport 4.1

Perform same commands (with appropriate slot/port) at the other end of the connection.

Add the ATM PVC at one end only:

addconn 4.1.100.100 bpx2 9.1.102.102


Port StatesPort State3.1 FAILED3.2 FAILED4.1 ACTIVE4.2 ACTIVE5.1 ACTIVE

Last Command: dspports


Port: 4.1 [ACTIVE ]Interface: LM-BXM CAC Override: EnabledType: UNI %Util Use: EnabledSpeed: 353208 (cps) Vc Shaping: DisabledShift: SHIFT ON HCF (Normal Operation)SIG Queue Depth: 640 Port Load: 0 %

Protocol: NONE SVC Channels: 0 SVC VPI Min: 0 SVC VPI Max: 0 SVC Bandwidth: 0 (cps)

This Command: cnfport 4.1

NNI Cell Header Format? [N]:


Local Remote Remote Route Channel NodeName Channel State Type Avoid COS O 3.1.1.55 )bpx1 9.1.13.58 Failed cbr 3.1.1.58 bpx1 9.1.14.32 Failed cbr 3.1.1.534 bpx1 9.1.14.37 Failed cbr 3.1.1.626 )bpx1 9.1.13.240 Failed cbr 3.1.1.1011 bpx1 9.1.14.33 Failed cbr 3.1.1.11253 )bpx1 9.1.13.119 Failed cbr 3.1.1.13824 bpx1 9.1.14.36 Failed cbr 3.2.1.22 bpx1 9.1.14.38 Failed cbr 3.2.1.159 )bpx1 9.1.7.57 Failed cbr 3.2.1.385 bpx1 9.1.14.34 Failed cbr 3.2.1.753 )bpx1 9.1.7.55 Failed cbr 3.2.1.818 bpx1 9.1.14.39 Failed cbr 3.2.1.15324 bpx1 9.1.14.35 Failed cbr

This Command: dspcons

Continue direction - Next/Quit? (n/q)

MAJOR ALARM


Local Remote Remote Route Channel NodeName Channel State Type Avoid COS O 3.2.1.16000 )bpx1 9.1.7.56 Failed cbr 4.2.5.20 bpx1 9.1.71.25 Ok vbr 5.1.1.18 bpx1 9.1.8.32 Ok cbr 9.1.5.16 bpx1 9.1.5.19 Ok cbr 9.1.5.17 bpx1 9.1.12.16 Ok vbr 9.1.5.18 bpx1 9.1.6.33 Ok vbr 9.1.5.19 bpx1 9.1.5.16 Ok cbr 9.1.5.20 bpx1 9.1.12.17 Ok vbr 9.1.5.21 bpx1 9.1.6.34 Ok vbr 9.1.5.22 bpx1 9.1.12.18 Ok vbr 9.1.5.23 bpx1 9.1.12.22 Ok vbr 9.1.5.24 bpx1 9.1.6.20 Ok vbr 9.1.5.25 bpx1 9.1.6.17 Ok vbr

This Command: dspcons

Continue direction - Next/Previous/Quit? (n/p/q)

MAJOR ALARM


Total Errors

Code Out of Loss of Frame HCS Tx Cell Cell CellLine Errors Frames Signal BitErrs Errors Dropped Errors Oofs 3.1 94K 115 35 - 15K 0 - - 3.2 13K 19 6 - 820 0 - - 4.1 - 0 1 - 21 0 - - 4.2 - 0 1 - 28 0 - - 5.1 89 19 14 - 2717 0 - -

Last Command: dsplnerrs

Next Command:

MAJOR ALARM


Alarm summary (Configured alarm slots: None)Connections Failed: 14TRK Alarms: NoneLine Alarms: 2 MajorsCards Failed: NoneSlots Alarmed: None Connection A-bit/AIS Alarms: 46Missing Cards: NoneRemote Node Alarms: None

Interface Shelf Alarms: 1 MajorASM Alarms: None

Last Command: dspalms

Next Command:

MAJOR ALARM

introduction to wan switching presented by drew spesard, internetwork experts (ccie #1495) &...

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