Expert Reference Series of White Papers. Cisco Service Provider Next Generation Networks

Transcription

1 Expert Reference Series of White Papers Cisco Service Provider Next Generation Networks COURSES

2 Cisco Service Provider Next Generation Networks Johnny Bass - Senior Global Knowledge Instructor, CCIE #6458, CCSI #97168, CCNP, CCDA, CCNP-SP Introduction What is Cisco Service Provider Next Generation Networks (IP NGN), and why do we care? This white paper will answer those questions and examine some of the technologies that are used within those networks. It will also provide examples of configurations for some of those platforms and contrast the differences in the types of operating systems. What Is Cisco IP NGN? According to Cisco, IP NGN is a platform for the Connected Life. Okay, what does that really mean? It is an infrastructure for voice, video, mobile, and cloud, or managed services based on Cisco products including the CRS Series, ASR Series (such as ASR 1000 running IOS-XE and ASR 9000 running IOS-XR), and different switch series, such as 6500, Metro Ethernet Series, and possibly Nexus Series. Other than some very subtle differences, IOS and IOS-XE look the same. The difference is that IOS is a monolithic operating system (OS) and IOS-XE (and IOS-XR) is a modular OS. Theoretically, a modular OS should be more stable than a monolithic OS since there is a separation of control plane and data plane, and a separation of processes. Therefore, if there is a failure in process or at the control plane, the data plane can continue to pass traffic based on last known information. Service providers agree that the Carrier Ethernet and IP/Multiprotocol Label Switching (MPLS) technology is and will be the way to next-generation networks. Some of the service provider challenges are to maintain growth and profitability. Service providers need to Accommodate surging demand for broadband services; maintain competitive residential and business service offerings Avoid service commoditization by offering new and premium services Strengthen profitability by increasing revenue while reducing total cost of ownership Migrate existing legacy ATM/Frame Relay networks to more cost-effective Carrier Ethernet or MPLS services Protect and grow business services in parallel with consumer services. Cisco IP NGN carrier Ethernet design incorporates multiple networking technologies to provide optimal flexibility for current and next-generation service offerings. Ethernet over MPLS (EoMPLS) Layer 3 Protocol Independent Multicast-Source Specific Multicast (PIM-SSM) Copyright 2013 Global Knowledge Training LLC. All rights reserved. 2

3 MPLS VPN IP over dense wavelength-division multiplexing (IPoDWDM) Hierarchal Virtual Private LAN Service (H-VPLS) IEEE 802.1ad; as well as emerging Ethernet, IP, and MPLS technologies. Basic Cisco design for NGN Routing + MPLS Design Must Provide Provider Edge (PE)-to-PE Routes (and Label Switched Paths) - PE needs /32 routes to other PEs - PE placement shouldn t matter Single BGP Autonomous System Number (ASN) Figure 1. Routing + MPLS Design Conventional Wisdom Says Advertise infrastructure (e.g., PE) routes in Interior Gateway Protocol (IGP) for reachability between PE routers. Advertise infrastructure (e.g., PE) labels in Label Distribution Protocol (LDP) to establish a label switch path between PE routers. Segment IGPdomains (i.e., ISIS L1/L2 or OSPF Areas) to add control. Keep in mind that summarization is not allowed at the boarders; this would be disruptive to the label switch path. Copyright 2013 Global Knowledge Training LLC. All rights reserved. 3

4 Figure 2. The Routing + MPLS Design Conventional Wisdom may not be good enough in environments with large IGP database size: a concern for fast(er) convergence and for network stability; or networks with large LDP databases. Figure 3. Routing + MPLS Design Divide & Conquer Game Plan is to disconnect and isolate IGP domains (No more end-to-end IGP view). You can leverage BGP for infrastructure (i.e., PE) routes and labels. Copyright 2013 Global Knowledge Training LLC. All rights reserved. 4

5 Figure 4. Routing + MPLS Design Divide & Conquer end results are that there are separate control plane flows (RIB/FIB Tables) and data plane flows. As an Example - PE31 Reachability from PE11: Figure 5. Reachability between PE routers would be label switch, rather than IP routed. There would be a label stack that includes an inside label derived by BGP and an outside label derived by the LDP per domain. Copyright 2013 Global Knowledge Training LLC. All rights reserved. 5

6 Routing + MPLS Design Divide & Conquer 1. The IGP is restricted to carry only the internal routes Non-zero or L1 area carries only routes for that area Backbone carries only backbone route - Unlike OSPF, ISIS Backbone Would Carry Both L1 and L2 Routes. Since L1->L2 (or L1->L1) Redistribution Cannot Be Avoided (yet). Figure PE redistributes its loopback into IGP as well as ibgp+label Figure PE peers with its local area border routers (ABRs) using ibgp+label ABRs act as Route-reflectors (RR) ABRs reflect _only_ Infrastructure (i.e. PE) routes RRs also in the backbone Copyright 2013 Global Knowledge Training LLC. All rights reserved. 6

7 Figure ABR, as RR, changes the BGP Next-hop to itself On each BGP advertised routes Figure PEs separately peer using ibgp for Services Dedicated RRs for IPv4/6, VPNv4/6, L2VPN, etc. Copyright 2013 Global Knowledge Training LLC. All rights reserved. 7

8 Example - L3VPN Services Figure 10. PE11 sends L3VPN traffic for an L3VPN prefix A to PE31 Figure 11. Routing + MPLS Design scales to higher numbers of routers (1000+). The key is BGP and MPLS label stacking capabilities. All routes are known by the PE, but not all routes are known but the intermediate routers. Key Protocols Network IGP Either ISIS or OSPF Multiprotocol BGP Multi-Protocol Label Switching (MPLS) IPv4 and IPv6 both unicast and multicast Protocol Independent Multicast (PIM and PIMv6) Copyright 2013 Global Knowledge Training LLC. All rights reserved. 8

9 Overview of Key Protocols and their Configurations Interior Gateway Protocols come in two flavors Intermediate System to Intermediate System (ISIS) Open Shortest Path First (OSPF) Open Shortest Path First (OSPF) Let s do a quick comparison of each protocol. OSPF ISIS Dijkstra algorithm Dijkstra algorithm OSPF natively built to route IPv4 (OSPFv2) or IPv6 (OSPFv3) IS-IS natively OSI, but supports IPv4, IPv6, Decnet Phase 5, IPX, and Layer 2 routing (TRILL, FabricPath) Router Types: Router Types: Internal routers Level 1 ABR Level 1 / 2 Backbone Level 2 ASBR Level 3 4 network types 2 network types (5 in a Cisco network) 11 or 12 LSA Types 2 types of LSP (OSPFv2 verses OSPFv3) 6 types of areas 2 types of levels (areas) Area number and router ID in the format of IPv4 address NET has area and system ID embedded in it for both OSPFv2 and OSPFv3 Table 1. Comparison of OSPF and ISIS Multiprotocol Border Gateway Protocol (BGP) BGP is a distance vector protocol with enhancements: - Reliable updates - Triggered updates only - Path attributes Designed to scale to huge internetworks (407,000 routes on the Internet) Is not designed for speed Virtual Routing and Forwarding (VRF) VRF is a technology implemented in the IP network routers that allows multiple instances of a routing table to exist on the same router at the same time. Copyright 2013 Global Knowledge Training LLC. All rights reserved. 9

10 Each VRF is independent Duplicate (or overlapping) IP subnets can exist in different VRFs without conflicting with each other. Multi-Protocol Label Switching (MPLS) MPLS was initially targeted for Service Provider customers; however, Enterprises have begun to show interest in deploying this technology. MPLS compliments IP technology. It is designed to leverage the intelligence associated with IP Routing, and the Switching paradigm. MPLS consists of a Control Plane and a Forwarding Plane. The Control Plane builds what is called a Forwarding Table, while the Forwarding Plane forwards packets to the appropriate interface (based on the Forwarding Table). The efficient design of MPLS uses Labels to encapsulate IP packets. A Forwarding Table lists Label Values, which are each associated with determining the outgoing interface for every network prefix. Cisco IOS Software supports two signaling mechanisms to distribute labels: Label Distribution Protocol (LDP) and Resource Reservation Protocol/Traffic Engineering (RSVP / TE). Configuration Examples IOS, IOS-XE and IOS-XR ISIS IOS/IOS-XE router#configure term router(config)# router isis isp router(config-router)# net d c router(config-router)# is-type level-2-only router(config-router)#exit router(config)# interface Gigabitethernet 0/3 router(config-if)#ip router isis isp ISIS IOS-XR router# configure router(config)# router isis isp router(config-isis)# net d c router(config-isis)# is-type level-2-only router(config-isis)# interface Gigabitethernet 0/1/0/3 router(config-isis-if)# address-family ipv4 unicast router(config-isis-if-af)# commit Copyright 2013 Global Knowledge Training LLC. All rights reserved. 10

11 OSPF IOS/IOS-XE router#configure term router(config)# router ospf 1 router(config-router)#router-id router(config-router)# network area 0 or router(config-router)# interface Gigabitethernet 0/3 router(config-if)#ip ospf 1 area 0 OSPF IOS-XR router# configure router(config)# router ospf 1 router(config-ospf)#router-id router(config-ospf)#area 0 router(config-ospf-ar)# interface Gigabitethernet 0/1/0/3 router(config-ospf-ar)# commit BGP IOS/IOS-XE router#configure term router(config)# router bgp router(config-router)#bgp router-id router(config-router)#network mask router(config-router)#neighbor remote-as router(config-router)#neighbor update-source loopback 0 router(config-router)#neighbor next-hop-self BGP IOS-XR router#configure router(config)#feature bgp router(config)#router bgp router(config-bgp)#router-id router(config-bgp)# address-family ipv4 unicast router(config-bgp-af)#network /24 router(config-bgp-af)#neighbor router(config-bgp-nbr)#remote-as router(config-bgp-nbr)#address-family ipv4 unicast router(config-bgp-nbr-af)#next-hop-self Copyright 2013 Global Knowledge Training LLC. All rights reserved. 11

12 router(config-bgp-nbr-af)#update-source loopback 0 router(config-bgp-nbr-af)#commit VRF IOS/IOS-XE router(config)#ip vrf Cust1 router(config-vrf)#rd 19920:1 router(config-vrf)#route-target export 19920:1 router(config-vrf)#route-target import 19920:1 router(config-vrf)#interface Fastethernet 0/0.10 router(config-if)#encapsulation dot1q 10 router(config-if)#ip vrf forwarding Cust1 router(config-if)#ip address router(config-if)#router ospf 10 vrf Cust1 router(config-router)#router-id router(config-router)#network area 10 router(config-router)#router bgp router(config-router)#address-family ipv4 vrf Cust1 router(config-router-af)#redistribute ospf 10 vrf Cust1 match internal external 1 external 2 VRF IOS-XR router(config)#vrf Cust1 router(config-vrf)#address-family ipv4 unicast router(config-vrf)#route-target export 19920:1 router(config-vrf)#route-target import 19920:1 router(config-vrf)#interface Gigabitethernet 0/2/0/4.10 router(config-if)#dot1q vlan 10 router(config-if)#vrf Cust1 router(config-if-vrf)#ipv4 address router(config-if-vrf)#router ospf 10 router(config-ospf)# vrf Cust1 router(config-ospf-vrf)#router-id router(config-ospf-vrf)#area 10 router(config-ospf-vrf)#interface Gigabitethernet 0/2/0/4.10 router(config-if)#exit router(config-ospf-vrf)# router(config-ospf)#router bgp router(config-bgp)#vrf Cust1 Copyright 2013 Global Knowledge Training LLC. All rights reserved. 12

13 router(config-bgp-vrf)#rd 19920:1 router(config-bgp-vrf)#address-family ipv4 unicast router(config-bgp-vrf-af)# redistribute ospf 1 router(config-bgp-vrf-af)#commit MPLS Configuration IOS/IOS-XE on P Router router(config)#mpls ldp router-id loopback 0 router(config)#interface Fastethernet 0/0 router(config-if)#ip address router(config-if)#mpls ip router(config)#interface Fastethernet 1/0 router(config-if)#ip address router(config-if)#mpls ip router(config-if)#router ospf 1 router(config-router)#router-id router(config-router)#network area 0 MPLS Configuration IOS/IOS-XE on PE Router router(config)#mpls ldp router-id loopback 0 router(config)#interface loopback 0 router(config-if)#ip address router(config)#interface Fastethernet 1/0 router(config-if)#ip address router(config-if)#mpls ip router(config-if)#router ospf 1 router(config-router)#router-id router(config-router)#network area 0 router(config-router)#network area 0 router(config-router)#router bgp router(config-router)#address-family vpnv4 router(config-router-af)#neighbor activate router(config-router-af)#neighbor send-community extended MPLS Configuration IOS-XR P Router router(config)# mpls ldp router(config-ldp)#router-id loopback 0 router(config-ldp)#interface Gigabitethernet 0/2/0/1 Copyright 2013 Global Knowledge Training LLC. All rights reserved. 13

14 router(config-ldp-if)#interface Gigabitethernet 0/2/0/2 router(config-ldp-if)#exit router(config)# router ospf 1 router(config-ospf)#router-id router(config-ospf)#area 0 router(config-ospf-ar)# interface Gigabitethernet 0/2/0/1 router(config-ospf-ar)# interface Gigabitethernet 0/2/0/2 MPLS Configuration IOS-XR PE Router router(config)#mpls ldp router(config-ldp)#router-id loopback 0 router(config-ldp)#interface Gigabitethernet0/1/0/1 router(config-ldp)#exit router(config)#interface loopback 0 router(config-if)#ip address router(config-if)#router ospf 1 router(config-ospf)#router-id router(config-ospf)#area 0 router(config-ospf-ar)#interface loopback 0 router(config-ospf-ar)#interface Gigabitethernet0/1/0/1 router(config-ospf-ar)#router bgp router(config-bgp)#address-family vpnv4 unicast router(config-bgp-af)#neighbor router(config-bgp-af-nbr)#remote-as router(config-bgp-af-nbr)#update-source loopback 0 Conclusion In today s Services Providers networks, they leverage technology to deal with the demands of their clients and network traffic. The networks have to be able to perform at or above those expected levels and be able to be flexible enough to handle future requirements (to a point). This paper has given you a taste of some of those technologies and the method that providers are using to scale too much larger networks. I have also given you examples of pieces of the configurations that might be on the different Cisco platforms. If you re interested in more, see the related courses below. Learn More SPNGN1 Building Cisco Service Provider Next-Generation Networks, Part 1 SPNGN2 Building Cisco Service Provider Next-Generation Networks, Part 2 Copyright 2013 Global Knowledge Training LLC. All rights reserved. 14

15 SPROUTE Deploying Cisco Service Provider Network Routing SPADVROUTE Deploying Cisco Service Provider Advanced Routing SPCORE Implementing Cisco Service Provider Next-Generation Core Network Services SPEDGE Implementing Cisco Service Provider Next-Generation Edge Network Services IPv6FD IPv6 Fundamentals, Design and Deployment V3.0 AMPLS - Advanced Implementing and Troubleshooting MPLS VPN Networks MPLST - MPLS Traffic Engineering and Other Features ASR9K - ASR 9000 Series Essentials Cisco XR Series Essentials CRS-1 - Cisco CRS-1 Essentials Visit or call COURSES ( ) to speak with a Global Knowledge training advisor. About the Author Johnny Bass has been in the networking industry since the late 1980s, specializing on Cisco System products since 1990 and has worked extensively in the Aerospace, Health Care, and Service Provider industries, providing network design, education, and technical support expertise. Holding both CCIE and CCSI credentials, Johnny has a proven record of teaching and consulting on Cisco Routing, Switching, Design, Implementation, and Support. During his tenure as a Senior Instructor with Global Knowledge, Johnny has developed extensive experience teaching CCNP/CCNP-SP/CCVP/Cisco Nexus and CCIE R&S courses. This experience has also allowed him to excel in the role of Course Director and Subject Matter Expert, with technical responsibility for Global Knowledge s North American CCIE R&S curriculum and Service Provider Technical Segment, including the Cisco CCIE 360 program for Routing and Switching; IPv6 Fundamentals, Design and Development; Building Cisco Service Provider Next-Generation Networks, Part 1 and Part 2; Deploying Cisco Service Provider Network Routing; Deploying Cisco Service Provider Advanced Routing; Implementing Cisco Service Provider Next-Generation Core Network Services; Implementing Cisco Service Provider Next-Generation Edge Network Services. Johnny is also the author of the CCIE Routing & Switching Written Exam Boot Camp currently running in Europe. Johnny is a Cisco 360 R&S Master instructor; the first to achieve this level outside of the organization that created the program. In addition to his teaching engagements, Johnny is the owner and President of Bass Consulting Services, Inc, a network engineering consultancy based outside of Seattle, WA specializing with service provider and large enterprise networks for design, configuration, and troubleshooting support. Johnny lives in Gig Harbor Washington with his wife (Tiffany) and children (Sean and Cayman). Hobbies are family, golf, scuba diving and music production. Copyright 2013 Global Knowledge Training LLC. All rights reserved. 15