View
217
Download
3
Category
Preview:
Citation preview
©1999 Raj JainOPNETWORK’99
1
Current Trends inCurrent Trends inNetworking Traffic ManagementNetworking Traffic Management
and Quality of Serviceand Quality of Service
Raj JainThe Ohio State University
Raj JainThe Ohio State University
2
FutureFuture
All I want you to tell me is what will be thenetworking technology in the year 2000.
JoanQuiglyJoan
Quigly
WhiteHouse
Astrologer
WhiteHouse
Astrologer
©1999 Raj JainOPNETWORK’99
2
FutureFuture
All I want you to tell me is what will be thenetworking technology in the year 2000.
JoanQuigly
JoanQuigly
WhiteHouse
Astrologer
WhiteHouse
Astrologer
©1999 Raj JainOPNETWORK’99
3
OverviewOverviewq 10 Trends in Networkingq QoS Approaches:
m ATMm IEEE 802.1Dm Integrated Servicesm Differentiated Servicesm MPLS
q Design Philosophies of each and problems
These slides are available athttp://www.cis.ohio-state.edu/~jain/talks/opnet99.htm
©1999 Raj JainOPNETWORK’99
4
Ten Networking TrendsTen Networking Trends 1. Faster Media
2. More Traffic
3. Traffic > Capacity
4. Data > Voice
5. ATM in Backbone
6. Everything over IP
7. Differentiation Not Integration
8. Back to Routing From Switching
9. Traffic Engineering
10. Other Trends
©1999 Raj JainOPNETWORK’99
5
Dime SaleDime Sale
One Megabit memory, One Megabyte disk,One Mbps link, One MIP processor, 10 cents each.....
©1999 Raj JainOPNETWORK’99
6
Trend 1: Faster MediaTrend 1: Faster Mediaq One Gbps over 4-pair UTP-5 up to 100 m
Was 1 Mbps (1Base-5) in 1984.
q Dense Wavelength Division Multiplexing (DWDM)allows 64 wavelengths in a single fiber64×OC-192 = 0.6 TbpsOC-768 = 40 Gbps demonstrated in 1998.Was 100 Mbps (FDDI) in 1993.
q 11 Mbps in-building wireless networksWas 1 Mbps (IEEE 802.11) in 1998.
©1999 Raj JainOPNETWORK’99
7
Trend 2: More TrafficTrend 2: More Traffic
q Number of Internet hosts is growing super-exponentially.
q Traffic per host is increasing:
m Cable modems allow 1 to 10 Mbps access fromhome
m 6-27 Mbps over phone lines using ADSL/VDSL
q Bandwidth requirements are doubling every 4 months
©1999 Raj JainOPNETWORK’99
8
Trend 3: Traffic > CapacityTrend 3: Traffic > Capacity
Expensive Bandwidth
q Sharing
q Multicast
q Virtual Private Networks
q Need QoS
q Likely in WANs
Cheap Bandwidth
q No sharing
q Unicast
q Private Networks
q QoS less of an issue
q Possible in LANs
©1999 Raj JainOPNETWORK’99
9
Trend 4: Data > VoiceTrend 4: Data > Voice
q Voice traffic is growing linearlyData traffic is growing exponentially
q In 1998-99, data traffic on carrier networks exceededthe voice traffic.
q Everyone is trying to get into the data business:
m Phone Networks ⇒ High-speed frame relay
m Video Networks ⇒ Cable Modems
Voice
Data
1998
Traffic
Time
©1999 Raj JainOPNETWORK’99
10
Data > Voice (Cont)Data > Voice (Cont)
q Convergence: Data+Voice+VideoAT&T + TCI, Lucent+Ascend, Nortel+Baynetworks
Gateway
IP Network
PhoneNetwork
PhoneNetwork
Gateway
CSU/DSU
Phone Network
IPNetwork
IPNetwork
CSU/DSU
q Past: Data over Voice
q Future: Voice over Data
©1999 Raj JainOPNETWORK’99
11
Trend 5: ATM in BackboneTrend 5: ATM in Backboneq Most carriers including AT&T, MCI, Sprint, UUNET,
have ATM backbone
q Over 80% of the internet traffic goes over ATM
q ATM provides:
m Traffic management
m Voice + Data Integration: CBR, VBR, ABR, UBR
m Signaling
m Quality of service routing: PNNI
q ATM can’t reach desktop: Designed by carriers.Complexity in the end systems. Design favors voice.
©1999 Raj JainOPNETWORK’99
13
IEEE 802.1D ModelIEEE 802.1D Modelq Massive bandwidth. Simple priorities will do.q Up to eight priorities: Strict.
1 Background2 Spare0 Best Effort3 Excellent Effort4 Control load5 Video (Less than 100 ms latency and jitter)6 Voice (Less than 10 ms latency and jitter)7 Network Control
©1999 Raj JainOPNETWORK’99
15
Old House vs New HouseOld House vs New House
q New needs:Solution 1: Fix the old house (cheaper initially)Solution 2: Buy a new house (pays off over a long run)
©1999 Raj JainOPNETWORK’99
16
Trend 6: Everything over IPTrend 6: Everything over IP
q Data over IP ⇒ IP needs Traffic engineering
q Voice over IP ⇒ Quality of Service and Signaling
q Internet Engineering Task Force (IETF) is the centerof action.Attendance at ATM Forum and ITU is down.
©1999 Raj JainOPNETWORK’99
17
Integrated ServicesIntegrated Services1. Best Effort Service: Like UBR.2. Controlled-Load Service: Performance as good as in
an unloaded datagram network. No quantitativeassurances. Like nrt-VBR or UBR w MCR
3. Guaranteed Service: rt-VBRm Firm bound on data throughput and delay.m Like CBR or rt-VBR
q Need a signaling protocol: RSVPq Design philosophy similar to ATM
m Per-flowm End-to-endm Signaling
©1999 Raj JainOPNETWORK’99
20
Problems with IntServ+RSVPProblems with IntServ+RSVPq Complexity in routers: classification, schedulingq Not scalable with # of flows
⇒ Not suitable for backbone.q Need a concept of “Virtual Paths” or aggregated flow
groups for the backbone.q Need policy controls: Who can make reservations?
⇒ RSVP admission policy (rap) working group.q Receiver Based:
Need sender control/notifications in some cases.q Soft State: Need route/path pinning (stability).q No negotiation and backtrackingq Note: RSVP is being revived for MPLS and DiffServ
©1999 Raj JainOPNETWORK’99
21
Trend 7: Differentiation NotTrend 7: Differentiation NotIntegrationIntegration
q DiffServ to standardize IPv4 ToS byte’s first six bits
q Packets gets marked at network ingressMarking ⇒ treatment (behavior) in rest of the netSix bits ⇒ 64 different per-hop behaviors (PHB)
Hdr LenVer Tot Len4b 4b 8b 16b
Type of Service (ToS)
∫ d/dx⇒
©1999 Raj JainOPNETWORK’99
22
DiffServ (Cont)DiffServ (Cont)q Per-hop behavior = % of link bandwidth, Priority
q Services: End-to-end. Voice, Video, ...
m Transport: Delivery, Express Delivery,...Best effort, controlled load, guaranteed service
q DS group will not develop servicesThey will standardize “Per-Hop Behaviors”
q Marking based on static “Service Level Agreements”(SLAs). Avoid signaling.
©1999 Raj JainOPNETWORK’99
23
Problems with DiffServProblems with DiffServ
q End-to-end ≠ Σ per-HopDesigning end-to-end services with weightedguarantees at individual hops is difficult.Only Expedited Forwarding will work.
q Designed for static Service Level Agreements (SLAs)Both the network topology and traffic are highlydynamic.
q How to ensure resource availability inside thenetwork?
q DiffServ is unidirectional ⇒ No receiver control
©1999 Raj JainOPNETWORK’99
24
DiffServ Problems (Cont)DiffServ Problems (Cont)q QoS is for the aggregate not micro-flows.
Not intended/useful for end users. Only ISPs.
m Large number of short flows are better handled byaggregates.
m Long flows (voice and video sessions) need per-flow guarantees.
m High-bandwidth flows (1 Mbps video) need per-flow guarantees.
⇒ DiffServ alone is not sufficient for backbone.Signaling via RSVP will be required.
©1999 Raj JainOPNETWORK’99
25
Trend 8: Back to Routing FromTrend 8: Back to Routing FromSwitchingSwitching
q Routing: Based on address lookup. Max prefix match.⇒ Search Operation⇒ Complexity ≈ O(log2n)
q Switching: Based on circuit numbers ⇒ Indexing operation ⇒ Complexity O(1) ⇒ Fast and Scalable for large networks andlarge address spaces
164.107.61.201 3
©1999 Raj JainOPNETWORK’99
26
Multiprotocol Label SwitchingMultiprotocol Label Switchingq Label = Circuit number = VC Idq Ingress router/host puts a label.
Exit router strips it off.q Switches switch packets based on labels.
Do not need to look inside ⇒ Fast.q OC-192 (10 Gbps) routers from Nexabit.
⇒ Switching for traffic engineering, not for speed.
H R
R
R H
H
H
Unlabeled LabeledR
H
©1999 Raj JainOPNETWORK’99
27
Trend 9: Traffic EngineeringTrend 9: Traffic Engineeringq User’s Performance Optimization
⇒ Maximum throughput, Min delay, min loss, mindelay variation
q Efficient resource allocation for the provider⇒ Efficient Utilization of all links⇒ Load Balancing on parallel paths⇒ Minimize buffer utilizationm Current routing protocols (e.g., RIP and OSPF)
find the shortest path (may be over-utilized).q QoS Guarantee: Selecting paths that can meet QoSq Enforce Service Level agreementsq Enforce policies: Constraint based routing ⊇ QoSR
©1999 Raj JainOPNETWORK’99
28
1
4
32
5
Signaling and Admission control Policing
Routing
Shaping
Scheduling
Traffic Monitoring and feedback
7 6 Buffer Mgmt
Traffic Engineering ComponentsTraffic Engineering Components
©1999 Raj JainOPNETWORK’99
29
MPLS Mechanisms for TEMPLS Mechanisms for TEq Signaling, Admission Control, Routing
q Explicit routing of Label Switched Paths (LSPs)
q Constrained based routing of LSPsAllows both Traffic constraints and ResourceConstraints (Resource Attributes)
q Hierarchical division of the problem (Label Stacks)
q Danger: Too much too soon…again
©1999 Raj JainOPNETWORK’99
30
QoS Design ApproachesQoS Design Approachesq Massive Bandwidth vs Managed Bandwidthq Per-Flow vs Aggregateq Source-Controlled vs Receiver Controlledq Soft State vs Hard Stateq Path based vs Access basedq Quantitative vs Qualitativeq Absolute vs Relativeq End-to-end vs Per-hopq Static vs Feedback-basedq Homogeneous multicast vs heterogeneous multicastq 1-to-n multicast vs n-to-1 multicast
©1999 Raj JainOPNETWORK’99
31
Comparison of QoS ApproachesComparison of QoS ApproachesIssue ATM IntServ DiffServ MPLS IEEE
802.3DMassive Bandwidthvs ManagedBandwidth
Managed Managed Massive Managed Massive
Per-Flow vsAggregate
Both Per-flow Aggregate Both Aggregate
Source-Controlledvs ReceiverControlled
UnicastSource,Multicastboth
Receiver Ingress Both Source
Soft State vs HardState
Hard Soft None Hard Hard
Path based vsAccess based
Path Path Access Path Access
Quantitative vsQualitative
QuantitativeQuantitative+Qualitative
Mostlyqualitative
Both Qualitative
Absolute vs Relative Absolute Absolute MostlyRelative
Absolute+ relative
Relative
©1999 Raj JainOPNETWORK’99
32
Comparison (Cont)Comparison (Cont)Issue ATM IntServ DiffServ MPLS IEEE
802.3DEnd-to-end vs Per-hop
end-end end-end Per-hop end-end Per-hop
Static vs Feedback-based
Both Static Static Static Static
Homogeneousmulticast vsheterogeneousmulticast
Homo-geneous
Hetero-geneous
N/A Homo-geneous
N/A
1-to-n vs n-to-1 1-to-n 1-to-n N/A Both Bothmulticast
©1999 Raj JainOPNETWORK’99
33
10. Other Trends10. Other Trendsq Network Economy:
In 1999, revenues by Internet-based Corporationsexceed that of Internet equipment vendors
q Networking is the key to a Corporation’s(country’s/individual’s) success
q Security
q Information Glut ⇒ Intelligent agents forsearching, digesting, summarizinginformation
q Mobility
©1999 Raj JainOPNETWORK’99
34
SummarySummary
q Super-exponential increase in data traffic andvoice over IP ⇒ Traffic Engineering and QoS over IP
q ATM and Integrated Services are based on per-flowend-to-end guarantees using signaling.
q DiffServ provide aggregate per-hop treatment.Meaningful services yet to be designed.
q MPLS combines the best of ATM and IP.Must avoid becoming too complex too soon.
©1999 Raj JainOPNETWORK’99
35
ReferencesReferencesq References on MPOA, MPLS, and IP Switching,
http://www.cis.ohio-state.edu/~jain/refs/ipsw_ref.htm
q Quality of Service using Traffic Engineering overMPLS: An Analysis, http://www.cis.ohio-state.edu/~jain/papers/mpls-te-anal.htm
q IP Switching, http://www.cis.ohio-state.edu/~jain/cis788-97/ip_switching/index.htm
q References on QoS over IP, http://www.cis.ohio-state.edu/~jain/refs/ipqs_ref.htm
q IP Switching: Issues and Alternatives,http://www.cis.ohio-state.edu/~jain/talks/ipsw.htm
©1999 Raj JainOPNETWORK’99
36
References (Cont)References (Cont)q Quality of Service in IP Networks,
http://www.cis.ohio-state.edu/~jain/talks/ipqos.htm
q Requirements for Traffic Engineering over MPLS,draft-ietf-mpls-traffic-eng-01.txt
q Constraint-based LSP Setup using LDP, draft-ietf-mpls-cr-ldp-01.txt
©1999 Raj JainOPNETWORK’99
37
AcronymsAcronymsATM Asynchronous Transfer ModeCBR Constant Bit RateCDV Cell Delay VariationDS Differentiated ServicesDVD Digital Video DisksDWDM Dense Wavelength Division MultiplexingFDDI Fiber Distributed Data InterfaceIEEE Inst. of Elect. and Electronic EngineersIETF Internet Engineering Task ForceIP Internet ProtocolISP Internet Service Provider
©1999 Raj JainOPNETWORK’99
38
Acronyms (Cont)Acronyms (Cont)LAN Local Area NetworkLSP Label Switched PathMCR Minimum Cell RateMIPS Millions of Instructions Per SecondMPLS Multiprotocol Label SwitchingMPOA Multiprotocol over ATMOC Optical CarrierPHB Per-hop BehaviorPNNI Private Network-Node InterfaceQoS Quality of ServiceQoSR Quality of Service Routing
©1999 Raj JainOPNETWORK’99
39
Acronyms (Cont)Acronyms (Cont)RIP Routing Information ProtocolRSVP Resource Reservation ProtocolSLA Service Level AgreementToS Type of ServiceUBR Unspecified Bit RateUTP Unshielded Twisted PairVBR Variable Bit RateVC Virtual CircuitVP Virtual Path
Recommended