2. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP

3. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-2 Objectives Upon completion of this chapter, you will be able to perform the following tasks: Describe the basics of the Differentiated Services QoS model Identify the issues of deploying DiffServ QoS model in large-scale networks Configure and monitor QoS Policy Propagation via BGP (QPPB) Describe the basics of Web Caching Identify the issues of deploying differentiated Web Caching in large-scale networks Configure and monitor Web Caching Communication Protocol (WCCP) Policy Redirection

4. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-3 Quality of Service Accelerating the deployment of network services, by enabling predictable response for application traffic and service requirements Best-effort IP delivery is not good enough for all applications and services. Some services or applications need: Guaranteed bandwidth Low and predictable delay Limited bandwidth Requires BGP for propagation of classes of services

5. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-4 Web Caching Used to improve throughput and response times of frequently visited web pages Requires BGP for advanced web caching designs with multiple clusters of web cache devices

6. Large-Scale IP Quality of Service Overview www.cisco.com © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-5

7. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-6 Objectives Upon completion of this section, you will be able to perform the following tasks: Describe components of the Differentiated Services (DiffServ) IP QoS model Describe the role of IP Precedence in DiffServ model Describe the role of QoS group in Cisco’s QoS implementation List the QoS components deployed between the Service Provider and a customer Identify the challenges of deploying large-scale QoS solutions

8. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-7 QoS Conceptual Models Two conceptual models developed within IETF Integrated Services (IntServ) Differentiated Services (DiffServ) IntServ model does not scale New IP QoS mechanisms are available in IOS to support the DiffServ model in large environments

9. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-8 DiffServ Overview The main goal of DiffServ is to provide a scalable IP QoS framework Defined by IETF’s RFC2475; An architecture for DiffServ Complex traffic classification, marking, and conditioning is performed at network edge resulting in a per-packet Differentiated Services Code Point (DSCP) Core only performs ‘simple’ operations based on DSCP

10. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-9 Predefined DiffServ Service Classes Assured Forwarding RFC 2597 Guarantees bandwidth to a class Four standard classes Expedited Forwarding RFC 2598 Guarantees the lowest possible delay One standard class

11. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-10 QoS Building Blocks within Cisco IOS Edge classification is the most difficult task in large environments Classify Meter MarkPolice Forward Classify Meter MarkPoliceQueue Input Interface Output Interface Input Output EDGE: DiffServ model uses complex classification on network edges (i.e. access lists) EDGE: Marking is only performed at network edge. Based on initial classification a router can mark IP packets with DSCP, IP precedence or QoS group CORE: Classification in the core is based on DSCP, IP precedence or QoS group CORE: Queuing, scheduling and dropping is influenced by the simple classification

12. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-11 Marking of IP Packets IP precedence – high-order three bits in the Type of Service field in the IP header Diffserv Code Point (DSCP) – high order six bits in DS Field (RFC 2474, former ToS field) QoS group – internal tagging of packets in routers (requires reclassification on every hop)

13. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-12 Class Markers Buffer header IP packet IP header IP precedence or DSCP QoS group (information is lost once the packet leaves the router) IP precedence – 3 bits (8 classes) DSCP – 6 bits (64 classes) QoS group – 100 classes IP packets in router’s memory are stored in fixed-length “buffers” Frame header

14. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-13 QoS Functions Guaranteeing quality of service for: Applications (usually identified by TCP or UDP port numbers) Services (usually identified by IP addresses or IP networks) Service providers, as the name says, provide services and can also guarantee a certain level of quality to these services

15. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-14 Example – Classifying Outgoing Traffic Customer wants guaranteed bandwidth to and from the Internet (ISP2) Service Provider Service Provider Customer ISP2 EDGE: classification is simple – based on source interface EDGE (and CORE): queuing and scheduling based on the marking (IP precedence or DSCP)

16. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-15 Example – Classifying Incoming Traffic Customer wants guaranteed bandwidth to and from the Internet (ISP2) Service Provider Service Provider Customer ISP2 EDGE: classification is impossible in large networks; using access list does not scale

17. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-16 IP QoS Edge Mechanisms Admission control and policing Inbound Committed Access Rate (CAR) filters: per interface, IP ACL, or MAC address Packet classification and marking CAR filters or BGP-based CEF marking Global marking (IP precedence or DSCP field) Local marking (QoS group within the router)

18. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-17 IP QoS Core Mechanisms Queuing Weighted Fair Queuing (WFQ) influenced by IP precedence Class-based WFQ (very fast custom queuing based on IP precedence or QoS group) Congestion management Weighted Random Early Detection (WRED) influenced by IP precedence

19. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-18 Summary After completing this section, you should be able to perform the following tasks: Describe components of Differentiated Services (DiffServ) IP QoS model Describe the role of IP Precedence in DiffServ model Describe the role of QoS group in Cisco’s QoS implementation List the QoS components deployed between the Service Provider and a customer Identify the challenges of deploying large-scale QoS solutions

20. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-19 Review Questions Name the two predefined DiffServ service classes Name some QoS mechanisms available in the IOS Which QoS markers are available in the IOS? How can we mark IP packets with the help of BGP?

21. BGP Driven QoS Marking www.cisco.com © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-20

22. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-21 Objectives Upon completion of this section, you will be able to perform the following tasks: Describe the Cisco Express Forwarding (CEF) switching mechanism Describe the QoS packet classification and marking with CEF Describe the role of BGP in CEF-based QoS marking Configure QoS Policy Propagation with BGP (QPPB) Monitor and troubleshoot QPPB Deploy QPPB in large-scale BGP-based networks

23. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-22 QPPB Requirements QoS Policy Propagation through BGP requires the following: Cisco Express Forwarding (CEF switching) BGP Cisco 7200, 7500, or 12000 Cisco IOS release 11.1CC, 12.0, or later

24. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-23 Review: Standard IP Switching BGP Table AddressPrefixAS-PathCommunitiesOther attr.Next hop 10.0.0.0/842 1337:121.2.3.4... IP Routing Table AddressPrefix... Switching Cache PrefixNext-hopOutgoing interface --- /24---Ethernet 0 Address 1.2.3.0 Protocol conn. /81.2.3.410.0.0.0BGP IP address... ARP Cache MAC address... L2 header... 10.0.0.0/8MAC header 1.2.3.40c.00.11.22.33.44

25. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-24 Review: CEF Switching FIB Table (CEF Cache) BGP Table AddressPrefixAS-PathCommunitiesOther attr.Next hop 10.0.0.0/842 1337:121.2.3.4... IP Routing Table AddressPrefix... Next-hopOutgoing interfaceAddressProtocol BGP ARP cache Adjacency pointer... 1.5.4.1Ethernet 01.2.3.0OSPF ---Ethernet 01.5.4.0conn. MAC address... IP address... Layer 2 header... Adjacency Table IP address... 1.5.4.1MAC header Prefix /24 1.2.3.4---10.0.0.0/8 0c.00.11.22.33.441.5.4.1 10.0.0.0 /8 1.5.4.1

26. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-25 CEF Switching with QoS Packet Marking FIB Table (CEF Cache) BGP Table AddressPrefixAS-PathCommunitiesOther attr.Next hop 10.0.0.0/842 1337:121.2.3.4... IP Routing Table AddressPrefix... Next-hopOutgoing interfaceAddressProtocol BGP ARP cache Adjacency pointer... 1.5.4.1Ethernet 01.2.3.0OSPF ---Ethernet 01.5.4.0conn. MAC address... IP address... Layer 2 header... Adjacency Table IP address... 1.5.4.1MAC header Prefix /24 Precedence --- QoS group --- 1.2.3.4---10.0.0.0/837 BGP table map Precedence... QoS group... 0c.00.11.22.33.441.5.4.1 10.0.0.0/81.5.4.1 3 7

27. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-26 QoS Packet Marking with CEF Mark the routes in the BGP table Use BGP communities, AS paths, IP prefixes, or any other BGP attributes Set IP precedence or QoS group in IP routing table and FIB table Enable CEF packet marking on interface

28. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-27 Set IP Precedence or QoS Group in the IP Routing Table and FIB table-map route-map-name Router(config-router)# Specifies the route map used to set additional routing table attributes route-map name permit seq set ip precedence precedence set ip qos-group group Router(config)# Specifies IP precedence and QoS group values in the routing table/FIB table entry

29. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-28 Enable Per-Interface Packet Marking bgp-policy source ip-prec-map Router(config-if)# Applied to packets received through this interface Uses FIB to map packet source IP address to IP precedence Rewrites IP precedence in the packet bgp-policy source ip-qos-map Router# Applied to packets received through this interface Uses FIB to map packet source IP address to QoS group QoS group attached to the incoming packet

30. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-29 Enable Per-Interface Packet Marking (cont.) bgp-policy destination ip-prec-map Router(config-if)# Applied to packets received through this interface Uses FIB to map packet destination IP address to IP precedence Rewrites IP precedence in the packet bgp-policy destination ip-qos-map Router# Applied to packets received through this interface Uses FIB to map packet destination IP address to QoS group QoS group attached to the incoming packet

31. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-30 Monitoring and Troubleshooting QPPB show ip cef [prefix] [detail] router# Detailed CEF output shows the IP precedence value Router#show ip cef 10.1.1.0 detail 10.1.1.0/24, version 12, cached adjacency to Serial0/0.1 0 packets, 0 bytes, Precedence flash (3) via 10.3.0.2, 0 dependencies, recursive next hop 10.3.0.2, Serial0/0.1 via 10.3.0.0/30 valid cached adjacency Router# Router#show ip cef 10.1.1.0 detail 10.1.1.0/24, version 12, cached adjacency to Serial0/0.1 0 packets, 0 bytes, Precedence flash (3) via 10.3.0.2, 0 dependencies, recursive next hop 10.3.0.2, Serial0/0.1 via 10.3.0.0/30 valid cached adjacency Router#

32. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-31 Monitoring and Troubleshooting QPPB (cont.) show ip interface [interface] router# Shows whether QPPB is enabled on an interface Router#show ip interface Serial0 is up, line protocol is up Internet address is 10.3.0.2/30 Broadcast address is 255.255.255.255... Policy routing is disabled Network address translation is disabled WCCP Redirect outbound is disabled WCCP Redirect inbound is disabled WCCP Redirect exclude is disabled BGP Policy Mapping is enabled (output ip-prec-map) Router#show ip interface Serial0 is up, line protocol is up Internet address is 10.3.0.2/30 Broadcast address is 255.255.255.255... Policy routing is disabled Network address translation is disabled WCCP Redirect outbound is disabled WCCP Redirect inbound is disabled WCCP Redirect exclude is disabled BGP Policy Mapping is enabled (output ip-prec-map)

33. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-32 IP QoS Case Study Customer in AS 73 is a Premium customer All packets to and from AS 73 shall be sent with precedence flash AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router

34. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-33 Step #1 Distribute QoS Functions AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router Packets for AS73 marked with precedence flash Packets from serial interface marked with precedence flash

35. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-34 Step #2 Select QoS Mechanisms AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router Packets for AS73 marked with precedence flash Packets from serial interface marked with precedence flash CEF-based marking Inbound CAR filter on interface

36. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-35 Step #3 - Design Individual QoS Mechanisms (CEF Marking) AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router Mark BGP routes from AS 73 with special community (12:17) Configure community propagation Set FIB table based on BGP community Configure CEF packet marking for packets coming from adjacent AS

37. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-36 Mark Routes Coming from AS73 AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router router bgp 12 neighbor 1.2.3.4 remote-as 73 neighbor 1.2.3.4 route-map Premium in ! route-map Premium permit 10 set community 12:17 additive

38. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-37 Configure Community Propagation AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router router bgp 12 neighbor 2.3.4.5 remote-as 12 neighbor 2.3.4.5 send-community

39. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-38 Set FIB Table Based on BGP Community AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router router bgp 12 table-map PremiumCheck ! route-map PremiumCheck permit 10 match community 17 set ip precedence flash ! route-map PremiumCheck permit 20 set ip precedence 0 ! ip community-list 17 permit 12:17

40. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-39 Configure CEF Packet Marking AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router ip cef switch ! interface hssi 0/0 bgp-policy destination ip-prec-map ip route-cache cef

41. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-40 IP QoS and BGP Interaction Review IP QoS features work independently of BGP routing BGP is used only to propagate policies for source or destination IP prefixes through the network

42. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-41 Summary After completing this section, you should be able to perform the following tasks: Describe the Cisco Express Forwarding (CEF) switching mechanism Describe the QoS packet classification and marking with CEF Describe the role of BGP in CEF-based QoS marking Configure QoS Policy Propagation with BGP (QPPB) Monitor and troubleshoot QPPB Deploy QPPB in large-scale BGP-based networks

43. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-42 Review Questions What is a FIB table? How is BGP information translated into QoS information in the FIB table? Describe the configuration steps for QPPB How many CEF lookups are performed for each packet when QPPB is enabled?

44. Overview of Web Caching in Large Networks www.cisco.com © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-43

45. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-44 Objectives Upon completion of this section, you will be able to perform the following tasks: Describe Web Caching components Describe the need for differentiated Web Caching behavior Identify the challenges of deploying differentiated Web Caching behavior in large-scale networks

46. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-45 What is Web Caching? Web Caching is a technology used primarily to intercepts HTTP requests and serve them locally A web cache stores the information for further requests for the same content Web Cache Communication Protocol (WCCP) is a protocol used between a router and a web cache

47. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-46 Web Caching Example Access to non-cached web page Web Server Web Cache http://acme.com Redirect www.acme.com http://acme.com

48. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-47 Web Caching Example (cont.) Access to cached web page Web Server Web Cache Redirect www.acme.com http://acme.com The web cache device only needs to validate the web page

49. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-48 Service Provider Service Provider Why Web Caching? Among a large number of HTTP requests, many target a small number of most visited web pages Using a web cache can improve throughput and response times Estimate: 70% is web traffic and 50% of it is duplicate ISP2 Not enough bandwidth to accomodate all requests Poor response times because of congestion and distance

50. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-49 Web Cache Design Options What to cache: which sources or destinations should be serviced by a caching device; which applications should be serviced by a caching device - WCCP version 2 supports port numbers other than 80 Where to cache (at ingress, egress or both) Do we need to provide differentiated quality of service for web traffic originating from customers using different classes of service

51. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-50 Customer Where to cache Caching should be implemented as close to the source (customer or web server farm) as possible Caching devices may be located further away form the source (i.e. due to cost involved with a large number of caching devices) Service Provider Service Provider ISP2 Customers may use their own caching devices or proxies A service provider may deploy a large number of caching devices on ingress points (POPs) A service provider may deploy a small number of caching devices on egress points (close to NAPs) A service provider may deploy caching in front of its web server farm to offload static content to caching devices

52. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-51 Differentiated Web Caching WCCP design options: Caching for all users Caching for some users (requires an access list) Grouping users into caching clusters (requires multiple access lists) The first option is simple to configure The other two require access lists to identify users. It is difficult to maintain accurate access lists and is, therefore, not scalable

53. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-52 Summary After completing this section, you should be able to perform the following tasks: Describe Web Caching components Explain the need for differentiated Web Caching behavior Identify the challenges of deploying differentiated Web Caching behavior in large-scale networks

54. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-53 Review Questions What is the purpose of web caching? How can web caching affect other QoS features implemented in a network? What is WCCP? What are the problems of setting up standard web caching?

55. WCCP Policy Redirection www.cisco.com © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-54

56. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-55 Objectives Upon completion of this section, you will be able to perform the following tasks: Describe the differentiated Web Caching mechanism controlled by the BGP table Configure WCCP Policy Redirection Monitor and troubleshoot WCCP Policy Redirection Deploy WCCP Policy Redirection in large-scale BGP-based networks

57. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-56 WCCP Policy Redirection BGP provides a scalable solution for classifying packets and Web Cache users There may be multiple classes of networks assigned to different web caching clusters Web cache clusters may have different services enabled Web cache clusters may have different QoS guarantees

58. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-57 Customer Driven WCCP Policy Redirection A decision whether to use a web cache can be left to a customer A customer can use BGP communities to choose the caching option AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router 10/8 12:10 BGP community 12:10 is translated into internal WCCP tag 1 Customers network carries BGP community 12:10

59. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-58 Provider Driven WCCP Policy Redirection A decision whether to use a web cache for a specific customer is determined by the ISP according to the SLA The service provider sets the appropriate BGP community attribute AS 12 WAN Core Customer (AS 73)AS 24 NAP Router POP Router 10/810/8 12:10 BGP community 12:10 is translated into internal WCCP tag 1 A service provider assigns a customer to a class according to an SLA

60. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-59 Configuring WCCP Policy Propagation Router(config-router)# table-map name Router(config)# route-map name permit seq match... set ip wccp policy-tag Apply a route map to updates going from the BGP table into the routing table Set the policy tag within a route map

61. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-60 Configuring WCCP Policy Propagation (cont.) ip wccp version 2 Router(config)# WCCP policy redirection works if WCCP version 2 is used ip wccp web-cache policy {source | destination} policy-tag or ip wccp service-tag policy {source | destination} policy-tag Router(config)# Enables web caching for packets with source or destination matched in the FIB table if the packets have corresponding policy tags

62. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-61 Configuring WCCP Policy Propagation (cont.) ip wccp web-cache redirect {in | out} or ip wccp service-tag redirect {in | out} Router(config-if)# Enables web caching on an interface

63. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-62 Monitoring WCCP Policy Redirection show ip cef [prefix] [detail] router# Detailed CEF output shows WCCP tags Router#show ip cef 10.1.1.0 detail 10.1.1.0/24, version 35, cached adjacency to Serial0/0.1 0 packets, 0 bytes, wccp tag 1 via 10.3.0.2, 0 dependencies, recursive next hop 10.3.0.2, Serial0/0.1 via 10.3.0.0/30 valid cached adjacency Router# Router#show ip cef 10.1.1.0 detail 10.1.1.0/24, version 35, cached adjacency to Serial0/0.1 0 packets, 0 bytes, wccp tag 1 via 10.3.0.2, 0 dependencies, recursive next hop 10.3.0.2, Serial0/0.1 via 10.3.0.0/30 valid cached adjacency Router#

64. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-63 Monitoring WCCP Policy Redirection (cont.) show ip interface [interface] router# Shows whether WCCP is enabled on an interface Router#show ip interface Serial0 is up, line protocol is up Internet address is 10.3.0.2/30 Broadcast address is 255.255.255.255... Policy routing is disabled Network address translation is disabled WCCP Redirect outbound is enabled WCCP Redirect inbound is disabled WCCP Redirect exclude is disabled … Router#show ip interface Serial0 is up, line protocol is up Internet address is 10.3.0.2/30 Broadcast address is 255.255.255.255... Policy routing is disabled Network address translation is disabled WCCP Redirect outbound is enabled WCCP Redirect inbound is disabled WCCP Redirect exclude is disabled …

65. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-64 WCCP Policy Redirection Case Study A service provider has three types of users: Dial-up users Best-effort users Premium users Each group is assigned to a separate cluster of web cache devices A Premium customer is allowed to disable web caching

66. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-65 Case Study - Design The service provider uses four digits in BGP communities The third digit is used for web caching options ServiceBGP Community Dial-up Users387:1x0x Best Effort Users387:1x1x Premium Users387:1x2x No Caching387:1x3x

67. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-66 Case Study – Network Layout AS 387 Premium Customer Premium Customer ISP2 Best- effort Customer Best- effort Customer PSTN / ISDN Dial-up pools are inserted into BGP and marked with 387:1000 Premium customer is marked with 387:1020 if not already marked with 387:1030 Best-effort customer is marked with 387:1010 WCCP Policy Redirection based on BGP communities

68. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-67 Case Study – Dial-up Users AS 387 Premium Customer Premium Customer ISP2 Best- effort Customer Best- effort Customer PSTN / ISDN ip local pool DIALUP 192.168.10.1 192.168.10.254 ip route 192.168.10.0 255.255.255.0 null 0 ! router bgp 387 network 192.168.10.0 route-map SetCommunity ! route-map SetCommunity permit 10 set community 387:1000 !

69. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-68 Case Study – Best-effort Users AS 387 Premium Customer Premium Customer ISP2 Best- effort Customer Best- effort Customer PSTN / ISDN ip route 200.200.200.0 255.255.255.0 serial 0 tag 1010 ! router bgp 387 redistribute static route-map BestEffort ! route-map BestEffort permit 10 match tag 1010 set community 387:1010 set origin igp !

70. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-69 Case Study – Premium Users AS 387 Premium Customer Premium Customer ISP2 Best- effort Customer Best- effort Customer PSTN / ISDN ! Static Premium Customer ip route 150.1.1.0 255.255.255.0 serial 0 tag 1020 ! router bgp 387 redistribute static route-map Premium neighbor 192.168.1.2 remote-as 65001 neighbor 192.168.1.2 description BGP Premium neighbor 192.168.1.2 route-map Premium in ! route-map StaticPremium permit 10 match tag 1020 set community 387:1020 set origin igp ! route-map BGPPremium permit 10 match community 120 ! route-map BGPPremium permit 20 set community 387:1020 ! ip community-list 120 permit _387:..3._

71. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-70 Case Study – Policy Redirection AS 387 Premium Customer Premium Customer ISP2 Best- effort Customer Best- effort Customer PSTN / ISDN router bgp 387 table-map WCCP_PP ! route-map WCCP_PP permit 10 match community 100 set ip wccp 1 ! route-map WCCP_PP permit 20 match community 101 set ip wccp 2 ! route-map WCCP_PP permit 30 match community 102 set ip wccp 3 ! route-map WCCP_PP permit 1000 ! ip community-list 100 permit _387:..0._ ip community-list 101 permit _387:..1._ ip community-list 102 permit _387:..2._ ip cef ! ip wccp version 2 ip wccp 1 policy source 1 ip wccp 2 policy source 2 ip wccp 3 policy source 3 ! interface hssi1/0 ip wccp 1 redirect out ip wccp 2 redirect out ip wccp 3 redirect out !

72. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-71 Summary After completing this section, you should be able to perform the following tasks: Describe the differentiated Web Caching mechanism controlled by the BGP table Configure WCCP Policy Redirection Monitor and troubleshoot WCCP Policy Redirection Deploy WCCP Policy Redirection in large-scale BGP-based networks

73. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-72 Review Questions What is the purpose of using BGP for WCCP policy propagation? What is a WCCP tag? What is the relation between BGP attributes and WCCP tags? List the configuration steps to enable WCCP based on BGP attributes.

74. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-73 Summary After completing this chapter, you should be able to perform the following tasks: Describe the basics of the Differentiated Services QoS model Identify the issues of deploying DiffServ QoS model in large-scale networks Configure and monitor QoS Policy Propagation via BGP (QPPB) Describe the basics of Web Caching Identify the issues of deploying differentiated Web Caching in large-scale networks Configure and monitor Web Caching Communication Protocol (WCCP) Policy Redirection

75. © 2001, Cisco Systems, Inc. Policy Propagation Through BGP-74