MPLS Traffic Engineering &. Management Issues. Taesang Choi. 2001. 12. 7.
Internet Architecture Team. Electronics Telecommunications Research Institute ...
MPLS Traffic Engineering & Management Issues Taesang Choi 2001. 12. 7. Internet Architecture Team Electronics Telecommunications Research Institute
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Topics ▣ ▣ ▣ ▣
MPLS-TE Basics MPLS-TE Operational Issues MPLS Management Issues MPLS-TE Management Solutions
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MPLS-TE Basics
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What is Traffic Engineering? ▣ The task of mapping traffic flows onto an existing physical topology to facilitate efficient and reliable network operations ▣ Check mpls & tewg working group documents for more well-versed definitions ◈ Requirements for Traffic Engineering Over MPLS (RFC 2702) ◈ A Framework for Internet Traffic Engineering (draft-ietf-tewgframework-05.txt)
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Legacy Internet TE Efforts ▣ IGP Metric-Based TE ◈ Remember “fish problem?” ◈ Drawbacks ?“Blame Shifting”: only serves to move problem around ?Lacks granularity ?Instability
▣ Overlay Network Approach ◈ ATM core ringed by routers & overlaid PVCs on top of it ◈ Drawbacks ?Full mesh overhead ?Not well integrated ?Cell Tax ?ATM SAR speed KNOM Tutorial 2001
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MPLS-TE Advantages ▣ The physical path of the “traffic-engineered path” is not limited to what the IGP would choose as the shortest path to reach the destination ▣ Variously divisible traffic aggregation and disaggregation ▣ Maneuvering load distribution ▣ Stand-by secondary paths and precomputed detouring paths ▣ Strongly unified measurement and control for each “traffic-engineered path”
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Vocabulary ▣ LSP (Label Switched Path) ◈ the “traffic-engineered path”
▣ Primary and Secondary Paths ◈ an LSP can contain a primary path & zero or more secondary paths
▣ Named Path ◈ a sequence of explicit hops
LSP A Primary Path
Named Path 1 Secondary Path
LSP B Primary Path
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Secondary Path
Named Path 2
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Vocabulary – cont’d ▣ Traffic Trunk (TT) ◈ an aggregation of traffic flows going from an ingress to an egress ◈ forwarded through a common path with common TE requirements ◈ characterized by ?its ingress and egress ?FEC which is mapped to it ?a set of attributes that determines its behavioral characteristics
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Vocabulary – cont’d ▣ Types of LSPs ◈ Static LSPs ?no relevance to TE ◈ LDP signaled LSPs ?no relevance to TE ◈ RSVP/CR-LDP signaled LSPs ?Explicit-path LSPs ?Constrained-path LSPs ?Note: both of the two above are not mutually exclusive!
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Components of MPLS-TE ▣ Packet Forwarding Component ◈ MPLS, label switching itself
▣ Information Distribution Component ◈ IGP (OSPF/IS-IS) extension
▣ Path Selection Component ◈ Constrained Shortest Path First (CSPF) algorithm
▣ Signaling Component ◈ LDP, CR-LDP, and RSVP-TE
▣ Not all of these required!
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How everything fits into? Link attributes operator input LSP attributes
advertised by IGP-extension CSPF
computes
LSP paths
topology & resources
structured as
TED advertised by IGP-extension
RSVP signaling reservation
Link attributes modification KNOM Tutorial 2001
LSP establishment Routing table
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MPLS-TE Mechanisms ▣ LSP Routing ◈ with TE attributes (LSP & Link attributes) ◈ dynamic vs. explicit
▣ Traffic Protection (Resilience) ◈ secondary paths and fast reroute
▣ Path Reoptimization (Adaptivity) ▣ Load Sharing and Balancing ◈ LSP-level traffic bifurcation
▣ LSP Hierarchy ◈ forwarding adjacency LSPs, unnumbered links
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MPLS-TE Deployment and Operational Issues
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MPLS-TE Deployment Issues ▣ MPLS is proposed as a standard TE solution by IETF, BUT ◈ Vendor Interoperability problem ◈ Limitation in online path calculation ◈ Problems on Traffic Trunks ◈ Measurement and Control Issues
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Interoperability ▣ Vendor specific implementation details diverge! ◈ Almost everything but signaling standard might be different ◈ Using more than two heterogeneous families in a domain may cause unpredictable operational problems
▣ Need a unified abstraction system to hide, moderate, and arbitrate the differences
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Limitation in Online Path Calc. ▣ Online path calc. considers one LSP at a time ◈ undeterministic ◈ The order in which an LSP is calculated plays a critical role!
▣ Global optimization required ◈ Optimization tools that simultaneously examine each link’s resource constraints and the requirements of each LSPs all together are necessary
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Problems regarding to TT ▣ How to define traffic trunks? ◈ No standard ◈ Manual classification ?requires TE policies ?granularity and scalability concern ?practically, only dest. prefix based classification supported ?requires, so called, “policy routing” ◈ BGP-based classification ?Transit traffic whose route updates’next_hop is identical to the egress of an LSP are routed over the LSP ◈ Implicit classification by IGP
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Problems regarding to TT – cont’d ▣ How to map a traffic trunk’s attributes onto LSPs’ constraints? ◈ need a global view ◈ must be able to anticipate the effect, to some extent ◈ must be able to rationalize ?by simulations ?by measurements ?by policies ?by intuition? ?by experience?
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Measurement and Control ▣ Measurement ◈ provides rationale and fundamental bases to induce proper TE constraints for TTs and LSPs ?such as, traffic (demand) matrices, congestion indication, LSP statistics, etc. ◈ methods ?SNMP (various MIBs), CLI, Cisco Netflow and TMS, and/or JUNOS MPLS Statistics, RTFM probes, etc.
▣ Control ◈ manages TE policies ?policy editing, conflict check, enforcement, withdrawal, etc. ?customized to service specific policies, such as VPN policies
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MPLS-TE Operational Issues ▣ Prohibitive costs for manual provisioning for multi-node and multi-vendor environment ◈ Longer educational curve ◈ Single highly skilled operator or multiple vendor specific many operators ◈ Tighter and precise communications among them
▣ Error-prone manual configuration and hard to detect the semantic configuration errors (e.g., typos in path name) ▣ LSP operations diagnosis (e.g., when LSP setup fails, it is very difficult to pin point the exact reasons. The system doesn’t tell much useful info.)
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Configurable LSP Attributes ▣ Can specify the following attributes either for each LSP or for each path belonging to the LSP ◈ bandwidth (traffic profile in CR-LDP) ◈ constrained (dynamic) vs. explicit path ◈ affinity ◈ adaptivity ?reoptimize-timer, reoptimize-event ◈ resilience ?(stand by) secondary paths, fast reroute ◈ priority & preemption ?setup, hold ◈ route record ◈ hop-limit, cos, etc. KNOM Tutorial 2001
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Juniper Example
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Minimum MPLS Configuration ▣ Required of transit routers, as well as the ingress and egress [edit] interfaces { interface-name { logical-unit-number { family mpls; # required to enable MPLS on this intf. } } } protocols { mpls { interface (interface-name | all); # required to enable MPLS on this intf. } rsvp { interface interface-name; # required for RSVP signaled MPLS only } }
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Create a Named Path ▣ Named Path ◈ means a physical path from the ingress to the egress
▣ Named Path and LSP ◈ Configuring an LSP may require multiple named paths ?primary and secondaries ◈ can specify the same named path on any number of LSPs
▣ Syntax [edit protocols mpls] path path-name { address | host name ; }
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Create an LSP ▣ Rough Syntax [edit protocols mpls] label-switched-path lsp-path-name { to address; # egress address from address; # ingress address # lots of statements for setting various LSP attributes;
primary path-name { # lots of statements for setting various path attributes;
} secondary path-name { # lots of statements for setting various path attributes;
}
}
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Cisco Example
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Minimum MPLS Configuration ▣ Required of transit routers, as well as the ingress and egress ◈ ◈ ◈ ◈
Turn on MPLS tunnels Turn on CEF Turn on IS-IS or OSPF Syntax ? Router(config)# ip cef ? Router(config)# mpls traffic-eng tunnels
? Router(config-if)# mpls traffic-eng tunnels ? ? ? ?
Router(config-if)# ip rsvp bandwidth bandwidth Router(config)# router ospf process-id Router(config-router)# mpls traffic-eng area 0 Router(config-router)# mpls traffic-eng router-id loopback0
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Create a Named Path ▣ Named Path ◈ means a physical path from the ingress to the egress
▣ Named Path and LSP ◈ Configuring an LSP may require multiple named paths ?primary and secondaries ◈ can specify the same named path on any number of LSPs
▣ Syntax Router(config)# Router(config)# Router(config)# Router(config)#
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ip explicit-path name path-c7204-m5 enable next-address 10.2.0.29 next-address 10.2.0.34 next-address 10.2.0.33
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Create an LSP ▣ Rough Syntax Router(config)# interface tunnel 2003 Router(config-if)# description c7204-m402 Router(config-if)# ip unnumbered Loopback0 Router(config-if)# tunnel mode mpls traffic-engineering Router(config-if)# tunnel destination 203.255.255.234 Router(config-if)# tunnel mpls traffic-eng autoroute announce Router(config-if)# tunnel mpls traffic-eng priority 7 7 Router(config-if)# tunnel mpls traffic-eng bandwidth 10000 Router(config-if)# tunnel mpls traffic-eng path-option 1 explicit name path-c7204-m5 Router(config-if)# tunnel mpls traffic-eng record-route Router(config-if)# exit Router(config)# router traffic-engineering Router(config)# traffic-engineering filter 1 egress 10.14.0.111 255.255.255.255 Router(config)# router traffic-engineering Router(config)# traffic-engineering route 1 tunnel 2003
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MPLS FCAPS ▣ MPLS Configuration Management ◈ Automating complex MPLS configuration rules (including TE rules)
▣ MPLS Fault Management ◈ MPLS LSP status monitoring ◈ MPLS Traffic Trunks/LSP fault analysis ◈ Link/Node failure diagnosis
▣ MPLS Performance Management ◈ LSP traffic measurement and analysis ◈ MPLS network global optimization
▣ MPLS Accounting Management ◈ Mapping measured traffic data into billing purpose ◈ Mapping accounting data into admission control information
▣ MPLS Security Management KNOM Tutorial 2001
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MPLS Service Management ▣ SLA Provisioning & Monitoring management ◈ General MPLS service (e.g., traffic trunk lease) SLA ◈ Service specific MPLS service (e.g., MPLS VPN) SLA
▣ Inter-domain MPLS Management ◈ Protocol level distributed solution (e.g. inter-domain signaling such as GMPLS) is one thing ◈ and management of this mechanism from network administrator viewpoint is another
▣ Many issues are still left open
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MPLS TE Management Solutions
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TE Servers: Products Introduction ▣ WANDL, Inc. - MPLSView ® ◈ Automated data collection, layout, event collection and filtering (mainly focused on pre-configured LSPs) ◈ A quasi real-time view on the configuration of the network, including LSP set-up & state and per-LSP traffic flow ◈ Partnership with Cisco and Juniper
▣ Makesystems, Inc. - NetMaker ® ◈ Network engineering and simulation tool for IP and MPLS ◈ Merged to OPNET Technologies, Inc.
▣ Alcatel GRATE ▣ ETRI - Wise ® KNOM Tutorial 2001
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VPN Servers: Products Introduction ▣ Orchaestream ▣ Cisco’s VPN Solution Center ▣ Dorado ▣ ETRI - Wise
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Wise
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Wise addresses Questions ▣ How are packets routed in our network, and how are routing protocols configured ? ▣ Why is this link so congested, while others are underutilized ? ▣ Which path is the best fit for an LSP to serve a new VPN flow without QoS degradation ? ▣ Why is this LSP’s operational / signaling state down? ▣ How much would it be worse if this node (link) fails? ▣ How much would it be better if our MPLS network is globally optimized by recomputing all LSPs together? ▣ Can we achieve some traffic engineering goals by global LSP reoptimization, routing metric optimization, or a totally new capacity planning process?
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How! Wise™ Visualizing Network, Routing & VPN Topology and Behavior
TE/VPN Policies
MIB Values
Simulation Logics (CSPF, etc.)
Operational Status
Enforcing Routing, TE and VPN Policies
Routing Protocol Info. (TED) subnet subnet
IP, LSP & VPN Traffic Measurement Results Area 1
TE Path (LSP)
Area 2 Backbone Area
subnet
subnet
IGP Path
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Main Functionality ▣ LSP / VPN Configuration Management and Quasi-realtime Monitoring ▣ Versatile Views of IP, MPLS, Routing (OSPF and BGP), and VPN Topology ▣ TE and VPN Policy Management ▣ IP Traffic Measurement and Analysis for MPLS-TE and VPN Management ▣ Intelligent Path Computation, Recommendation, and Various Simulations
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Wise Architecture CSI (Common Service Interfaces)
GUI
Configuration Package
Measurement Package
Global Config Package
Misc Package
CORBA
TMS DB
TMS
CORBA
PS
CORBA
Traffic Measurement Results
RMS DB CORBA
Measured Traffic Data
RATE
SNMP Polling Results
COPS
RMS
PS DB
PIB
CORBA
TMS Agent
RMS Agent
COPS Agent
Cisco CLI
Junoscript Client
ACE CLI
Proxy Agent
SNMP
OSPF/BGP
CISCO Router
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Juniper Router
ACE2000
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Easy Steps to create LSP Tunnels and VPNs CORBA Configuration Package
Measurement Package
Global Config Package
Misc Package
GUI
CORBA
PS COPS
TMS Agent
RMS Agent
COPS Agent
Cisco CLI
JunOS CLI
ACE CLI
Proxy Agent
CLI/Telnet
CISCO Router
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Juniper Router
ACE2000
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Versatile Topology Views: IP IP Topology View
+ -
Seoul Suwon
A V P V L V
Taegu Taejon
Link Utilization: % 0 ~ 20
Kwangju Pusan
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20 ~ 40 40 ~ 60 60 ~ 80 80 ~ 100
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Versatile Topology Views: MPLS LSP Traffic MPLS View - LSP Tunnel Statistics
+ -
Seoul Suwon
A LSP Tunnel Intf: Tae-Suw-Seo, V 600Mbps P V L V
Per LSP Statistics
Taejon
LSP Name
Ingress
m10-to-m5 c7204-to-m10 m201-to-m5 m10-to-c7204
Kwangju
m5-to-m202
Taegu
Egress
BPS
203.255.255.232
203.255.255.235
2344556
203.255.255.236
203.255.255.232
24980
203.255.255.233 LSP Statistics:203.255.255.235 % 203.255.255.232 0 ~ 203.255.255.236 20 203.255.255.235
Pusan Show Path
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20 ~203.255.255.234 40 40 ~ 60 60 ~ 80 80 ~ 100
OK
47837593759 57843578 478593
Help
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Versatile Topology Views: MPLS Reserved Bw MPLS View - Reserved Bandwidth
+ -
Seoul Suwon
A V P V L V
Taegu Taejon
Reserved Bw: % 0 ~ 20
Kwangju Pusan
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20 ~ 40 40 ~ 60 60 ~ 80 80 ~ 100
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Versatile Topology Views: MPLS Affinity MPLS View - Affinity
+ -
Seoul Suwon
A V P V L V
Taegu Taejon
Affinity: Colors 1
Kwangju Pusan
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2 3 4 5
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Versatile Topology Views: MPLS Link & Tunnels MPLS View - Links and Tunnels
+ -
Seoul Suwon
A V P V L V
Taegu Taejon
Kwangju Pusan
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Versatile Topology Views:
Routing Protocols
Routing Protocol View - OSPF
+ IGP: OSPF Routing Protocol View - BGP A V
+
P V
-
ABR AS9270
L V
AS64514: Area0 A V
AS64515
P V L V
AS64513
AS64514
AS64512
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Versatile Topology Views: MPLS/BGP VPN Routing Protocol View - BGP
+ -
VPN#1
VPN#2
PE2: 203.255.255.233
PE1: 203.255.255.232
A V P V L V
VPN#2
VPN#1 PE5: 203.255.255.236
PE3: 203.255.255.234
PE4: 203.255.255.235 VPN Tunnels L2 Links Cisco VPN#2
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VPN#1
Juniper
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Various Simulations: Path Availability Check
MPLS View - Reserved Bandwidth
+ -
Seoul Suwon
Simulation - Path Availablity Check: Step 2 A V P V
Available Path was found. Do you want to see it?
L V
OK
Cancel
Taegu Taejon
Reserved Bw: % 0 ~ 20
Kwangju Pusan
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20 ~ 40 40 ~ 60 60 ~ 80 80 ~ 100
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Various Simulations: Link/Node Failure Simulation - Link/Node Failure: Step 1 MPLS View - Reserved Bandwidth
Simulation name: + Description: -
Tunnel Link Failure Simulation
Simulation date:
+ 2001/10/23 17:30
17
To:
18
Seoul
-
Duration
From:
This MPLS simulation View - is Reserved to see Bandwidth what happens when a link fails
A V P V L V
Seoul
hour 30
min.
23
day
Oct
hour 00
min.
23
day
Oct
Suwon
month 2001
year Suwon month 2001 year
A V P V
L Next >> V Simulation - Link/Node Failure: Step 2
Cancel
Traffic Flows thru Standby Select failed links or nodes from the Taejon Secondary map. Then, click the OK button. LSP
Taegu Taegu Taejon
Reserved Bw: %
OK
0 ~ 20
Kwangju Kwangju
Pusan Pusan
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20 Reserved ~ 40 Bw: % 40 ~ 60 0 ~ 20 60 ~ 80 20 ~ 40 80 ~ 100 40 ~ 60 60 ~ 80 80 ~ 100
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LSP/Network Traffic Measurement and Analysis LSP tunnel statistics
Name: Daily
Traffic Matrix File(F) Statstics(S)
View(V)
Tool(T)
Help(H)
Traffic Matrix Graphics Matrix Color Reserved File(F) Statstics(S) View(V) Tool(T) Help(H) LSP3 1000 Traffic Matrix Bandwidth: Matrix Color Transit Bound Help(H) Prefix File(F) Statstics(S) Graphics View(V) In.Out Tool(T) 2001 - 10 - 23 Weekly Monthly Yearly Graphics Matrix Color 129.254/16 Daily Transit In.Out Bound Prefix
kbps Graph
bps pps 2001-10-23 ~ 2001-10-23 129.254.191/24 Weekly Transit In.Out Bound Prefix AS 4323 bps pps bps ~ 2001-10-23 2001-10-23 203.255.254.130/27 Daily Monthly current : 343 bps AS 4323 AS 32 Yearly Weekly bps pps 63.43.62/24 Daily 2001-10-23 ~ 2001-10-23 maximum: 543 bps Monthly AS 32 AS 432 13.53/16 minimum : 132 bps Yearly 129.254.75/24 AS 432 AS 5654 54.33.53/24 234.23.123/24 AS 61232 211.75.163/24 src dest AS 4 AS 845 AS 12 AS 24 AS 2352 AS 5654 1000 AS 24 756 bps AS 41 AS 61232 AS 4 5/8 300 200 700 700 AS 4 500 AS 41 AS 865 AS 12 700 700 700 700 AS 865 AS 232 24 400 700 700 0 1 2 3AS 4 232 5 6 7 8 9 1 0 1129.254.75/24 1 1 2 1 3 1 4 1 5 1 6 1AS 7 1 8 1 9 2 0 2 1 2700 2 23 24 211.13.232.192/26AS 2352 700 400 400 700 AS 12 32.23/16 AS 845 700 400 400 400 pps AS 12 AS 24 234.23.123/24 current : 343 pps AS 24 AS 4 10/8 AS 12 maximum: 543 pps 211.13.232.192/26 minimum : 132 pps AS 4 AS 2352 AS 845 AS 2352 10/8 AS 845 1000 1000 AS 2352
Tunnel Statistics Prefix Matrix Relationship View AS Matrix Relationship View AS Matrix Table & Graph View
500
0 ~ 20 % 20~40 % 0 ~ 20 % 40~60 % 0 1 2 3 4 5 6 7 8 9 1 0 101 ~1 20 2 1% 320~40 1 4 1 5% 1 660~80 1 7 1 8% 1 9 2 0 2 1 2 2 2 3 2 4 32.23/16 20~40 %40~60 % 80 ~100 1 2 3% 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 AS 845 Print 40~60 %Save 60~80 % maxClose : 2343 60~80 % 80 ~100 % avg : 1234 min : 234 80 ~100 %
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