• • • ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Chapter 2: Static Routing Routing and Switching Essentials 6.0 Planning Guide Cisco Networking Academy Program Routing & Switching Essentials v6.0 Chapter 2: Static Routing ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential • •2.1 Static Routing Advantages •2.2 Configure Static and Default Routes •2.3 Troubleshoot Static and Default Routes § Chapter 2 - Sections & Objectives Cisco Networking Academy Program Routing and Switching Essentials v6.0 Chapter 2: Static Routing ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2.1 Implement Static Routes 2 - Static Routing 2.1 – Implement Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential •A router learns about remote networks in two ways: • •Manually entered into the route table using static routes •Static routes are not automatically updated and must be reconfigured when topology changes • •Dynamically (Automatically) learned using a routing protocol Reach Remote Networks 2.1 – Implement Static Routes 2.1.1 – Static Routing 2.1.1.1 – Reach Remote Networks ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Dynamic Routing ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Why Use Static Routing? Dynamic versus Static Routing 2.1 – Implement Static Routes 2.1.1 – Static Routing 2.1.1.2 – Why Use Static Routing? ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential When to Use Static Routes •Three uses for static routes: §Smaller networks that are not expected to grow §Routing to and from stub networks •Stub network accessed by a single route and has one neighbor •172.16.3.0 is a stub network §A single default route to represent a path to any network not found in the routing table •Use default route on R1 to point to R2 for all other networks • • • • • • • • • • Stub Networks and Stub Routers 2.1 – Implement Static Routes 2.1.1 – Static Routing 2.1.1.3 – When to Use Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Static Route Applications Use Static Routes To: §Connect to a specific network §Connect a stub router §Summarize routing table entries which reduces size of routing advertisements §Create a backup route in case a primary route link fails • 2.1 – Implement Static Routes 2.1.2 – Types of Static Routes 2.1.2.1 – Static Route Applications ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Standard Static Route §R2 configured with a static route to reach the stub network 172.16.3.0/24 § 2.1 – Implement Static Routes 2.1.2 – Types of Static Routes 2.1.2.2 – Standard Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Default route matches all packets and is used when a packet does not match a specific route in the routing table §Can be dynamically learned or statically configured §Default Static route uses 0.0.0.0/0 as the destination IPv4 address §Creates a Gateway of Last Resort §Common use is when connecting a company’s edge router to the ISP network §Router has only one router to which it is connected Default Static Route 2.1 – Implement Static Routes 2.1.2 – Types of Static Routes 2.1.2.3 – Default Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Multiple static routes can be summarized into a single network address •Destination networks must be contiguous •Multiple static routes must use the same exit interface or next hop •In figure, four networks is summarized into one summary static route Summary Static Route 2.1 – Implement Static Routes 2.1.2 – Types of Static Routes 2.1.2.4 – Summary Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Static routes that are used to provide a backup path §Used when primary route is not available §Configured with a higher administrative distance (trustworthiness) than the primary route §Example: EIGRP administrative distance equals 90. A floating static route with an AD of 91 or higher would serve as backup route and will be used if EIGRP route goes down. § § § Floating Static Route Floating Static Route 2.1 – Implement Static Routes 2.1.2 – Types of Static Routes 2.1.2.5 – Floating Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2.2 Configure Static and Default Routes 2 - Static Routing 2.2 – Configure Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ip route Command 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.1 –ip route Command ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Next-Hop Options §In this example, each router only has entries for directly connected network 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.2 – Next-Hop Options ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv4 Static Routes Next-Hop Options (Cont.) §R1 does not have an entry in its routing table for the R3 LAN network §In a static route next-hop can be identified by •Next-hop IP address •Router exit interface •Next-hop IP address and exit interface 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.2 – Next-Hop Options ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §In this example, only the next-hop IP address is specified §Before packet is forwarded the router must determine the exit interface to use (route resolvability) Configure IPv4 Static Routes Configure a Next-Hop Static Route 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.3 – Configure a Next-Hop Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §In example, when a packet is destined for 192.168.2.0/24 network, R1: •Looks for match (#1) and needs to forward packets to 172.16.2.2 •R1 must determine how to reach 172.16.2.2 first •Searches a second time for 172.16.2.0/24 (#2) and matches to exit interface s0/0/0 •Takes two routing table lookups, process referred to as recursive lookup •If the exit interface is “down” or “administratively down” then the static route configured with next-hop will not be installed in routing table Configure a Next-Hop Static Route (Cont.) 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.3 – Configure a Next-Hop Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Use the exit interface to specify next-hop so no other lookups are required §Administrative distance of static route is 1 § Configure a Directly Connected Static Route 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.4 – Configure a Directly Connected Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Cisco Express Forwarding (CEF) •default behavior on IOS 12.0 or later •provides optimized lookup •uses a Forwarding Information Base (FIB) which is a copy of the routing table and an adjacency table that includes Layer 2 addresses •no recursive lookup needed for next-hop IP address lookups § Configure a Directly Connected Static Route (Cont.) 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.4 – Configure a Directly Connected Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Both the exit interface and the next-hop IP address are specified §When exit interface is an Ethernet network, fully specified static route is used §Note: With CEF, a next-hop address could be used instead Configure a Fully Specified Static Route 2.2 – Configure Static and Default Routes 2.2.1 – Configure IPv4 Static Routes 2.2.1.5 – Configure a Fully Specified Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Default Static Route §Default static routes are commonly used when connecting: •An edge router to a service provider network •A stub router (a router with only one upstream neighbor router) §Default route is used when no other routes in the routing table match the destination IP 2.2 – Configure Static and Default Routes 2.2.2 – Configure IPv4 Default Routes 2.2.2.1 – Default Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure a Default Static Route Any packets not matching route entries are forwarded to 172.16.2.2 2.2 – Configure Static and Default Routes 2.2.2 – Configure IPv4 Default Routes 2.2.2.2 – Configure a Default Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §show ip route static displays just the static routes •S indicates static route •candidate default route indicated by * •/0 mask in route entry indicates none of the bits are required to match Verify a Default Static Route 2.2 – Configure Static and Default Routes 2.2.2 – Configure IPv4 Default Routes 2.2.2.3 – Verify a Default Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Packet Tracer – Configuring IPv4 Static and Default Routes 2.2 – Configure Static and Default Routes 2.2.2 – Configure IPv4 Default Routes 2.2.2.4 – Packet Tracer – Configuring IPv4 Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Lab – Configuring IPv4 Static and Default Routes 2.2 – Configure Static and Default Routes 2.2.2 – Configure IPv4 Default Routes 2.2.2.5 – Lab– Configuring IPv4 Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential The ipv6 route Command 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.1 – The ipv6 route Command ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential The ipv6 route Command (Cont.) §ipv6 unicast-routing enables the router to forward IPv6 packets 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.1 – The ipv6 route Command ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Each router only knows about directly connected networks •R1 can ping R2 (ipv6 2001:DB8:ACAD:4::2) but cannot ping R3 (ipv6 2001:DB8:ACAD:3::2) Next-Hop Options 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.2 – Next-Hop Options ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential § ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential § ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Next hop can be identified by an IPv6 address, exit interface, or both. §Destination is specified by one of three route types: •Next-hop static IPv6 route - Only the next-hop IPv6 address is specified •Directly connected static IPv6 route - Only the router exit interface is specified •Fully specified static IPv6 route - The next-hop IPv6 address and exit interface are specified Configure IPv6 Static Routes Next-Hop Options (Cont.) 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.2 – Next—Hop Options ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Static Routes Configure a Next Hop Static IPv6 Route Three next-hop static routes are configured on R1 As with IPv4, must resolve the route to determine the exit interface to use to forward the packet The IPv6 address matches the route for the directly connected network 2001:DB8:ACAD:4::/64 with the exit interface Serial 0/0/0. 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.3 – Configure a Next Hop Static IPv6 Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Alternative to next hop is to specify the exit interface §Packet destined for 2001:DB8:ACAD:3::/64 network, forwarded out Serial 0/0/0 – no other lookups needed Configure IPv6 Static Routes Configure a Directly Connected Static IPv6 Route 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.4 – Configure a Directly Connected Static IPv6 Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential §Fully specified static route must be used if IPv6 link-local address is used as next-hop Configure IPv6 Static Routes Configure a Fully Specified Static IPv6 Route 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.5 – Configure a Fully Specified Static IPv6 Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Static Routes Verify IPv6 Static Routes 2.2 – Configure Static and Default Routes 2.2.3 – Configure IPv6 Static Routes 2.2.3.6 – Verify IPv6 Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Default Routes Default Static IPv6 Route §Default static route matches all packets not specified in routing table • 2.2 – Configure Static and Default Routes 2.2.4 – Configure IPv6 Default Routes 2.2.4.1 – Default Static IPv6 Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Default Routes Configure a Default Static IPv6 Route §R1 is a stub router because it is only connected to R2 §More efficient to configure a default static IPv6 route in this topology 2.2 – Configure Static and Default Routes 2.2.4 – Configure IPv6 Default Routes 2.2.4.2 – Configure a Default Static IPv6 Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Default Routes Verify a Default Static Route §::/0 mask indicates that none of the bits are required to match § If a more specific match does not exist, the default static IPv6 route matches all packets. 2.2 – Configure Static and Default Routes 2.2.4 – Configure IPv6 Default Routes 2.2.4.3 – Verify a Default Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Default Routes Packet Tracer – Configuring IPv6 Static and Default Routes 2.2 – Configure Static and Default Routes 2.2.4 – Configure IPv6 Default Routes 2.2.4.4 – Packet Tracer – Configuring IPv6 Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure IPv6 Default Routes Lab – Configuring IPv6 Static and Default Routes 2.2 – Configure Static and Default Routes 2.2.4 – Configure IPv6 Default Routes 2.2.4.5 – Lab – Configuring IPv6 Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Floating Static Routes Floating Static Routes •Floating static routes have an administrative distance greater than the dynamic routing protocol or other static route §Used as backup routes §Administrative distance of common routing protocols •EIGRP = 90 •IGRP = 100 •OSPF = 110 •IS-IS = 115 •RIP = 120 §By default, AD of static route = 1 §Static route AD can be increased to make route less desirable until preferred route is lost § § 2.2 – Configure Static and Default Routes 2.2.5 – Configure Floating Static Routes 2.2.5.1 – Floating Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Floating Static Routes Configure a Floating Static Route Preferred router from R1 is to R2 (AD = 1) 2.2 – Configure Static and Default Routes 2.2.5 – Configure Floating Static Routes 2.2.5.2 – Configure an IPv4 Floating Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Floating Static Routes Test the IPv4 Floating Static Route 2.2 – Configure Static and Default Routes 2.2.5 – Configure Floating Static Routes 2.2.5.3 – Test the IPv4 Floating Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Floating Static Routes Test the IPv4 Floating Static Route (Cont.) 2.2 – Configure Static and Default Routes 2.2.5 – Configure Floating Static Routes 2.2.5.3 – Test the IPv4 Floating Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Floating Static Routes Configure an IPv6 Floating Static Route §Similar to IPv4 floating static routes 2.2 – Configure Static and Default Routes 2.2.5 – Configure Floating Static Routes 2.2.5.4 –Configure an IPv6 Floating Static Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Floating Static Routes Packet Tracer - Configuring Floating Static Routes 2.2 – Configure Static and Default Routes 2.2.5 – Configure Floating Static Routes 2.2.5.5 –Packet Tracer - Configuring Floating Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Static Host Routes Automatically Installed Host Routes •Host route is an IPv4 address with a 32-bit mask or IPv6 address with a 128-bit mask. §Automatically installed when IP address is configured §Configured as a static host route §Allows more efficiency for packets directed to the router §Local route marked with “L” (introduced in IOS 15) § 2.2 – Configure Static and Default Routes 2.2.6 – Configure Static Host Routes 2.2.6.1 – Automatically Installed Host Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Configure Static Host Routes Configure IPv4 and IPv6 Static Host Routes 2.2 – Configure Static and Default Routes 2.2.6 – Configure Static Host Routes 2.2.6.2 – Configure IPv4 and IPv6 Static Host Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2.3 Troubleshoot Static and Default Routes 2 - Static Routing 2.3 – Troubleshoot Static and Default Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Packet Processing with Static Routes Static Routes and Packet Forwarding PC1 sending packet to PC3 - Packet arrives on G0/0 R1 has no specific route to 192.168.2.0 so uses default route R1 encapsulates packet in new frame Frame forwarded out S0/0/0 2.3 – Troubleshoot Static and Default Routes 2.3.1 – Packet Processing with Static Routes 2.3.1.1 – Static Routes and Packet Forwarding ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Packet Processing with Static Routes Static Routes and Packet Forwarding (Cont.) Packet arrives on S0/0/0 interface on R2 R2 de-encapsulates the frame and looks for a route to the destination R2 has a static route to 192.168.2.0/24 out the Serial 0/0/1 interface R2 encapsulates the packet in a new frame and forwards out S0/0/1 2.3 – Troubleshoot Static and Default Routes 2.3.1 – Packet Processing with Static Routes 2.3.1.1 – Static Routes and Packet Forwarding ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Packet Processing with Static Routes Static Routes and Packet Forwarding (Cont.) R3 de-encapsulates the frame and sees a connected route to 192.168.2.0/24 out G0/0 R3 looks up the ARP table entry for 192.168.2.10 to find the Layer 2 MAC address for PC3 (ARP used if needed for PC3 MAC) •R3 encapsulates the packet in a new frame with the MAC address of the G0/0 interface as the source Layer 2 address and the MAC address of PC3 as the destination MAC address •Frame is forwarded out of G0/0 interface and packet arrives on the NIC interface of PC3 2.3 – Troubleshoot Static and Default Routes 2.3.1 – Packet Processing with Static Routes 2.3.1.1 – Static Routes and Packet Forwarding ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Troubleshoot IPv4 Static and Default Route Configuration Troubleshoot a Missing Route §Common IOS troubleshooting commands include: •ping •traceroute •show ip route •show ip interface brief •show cdp neighbors detail 2.3 – Troubleshoot Static and Default Routes 2.3.2 – Troubleshoot IPv4 Static and Default Route Configuration 2.3.2.1 – Troubleshoot a Missing Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Troubleshoot IPv4 Static and Default Route Configuration Troubleshoot a Missing Route (Cont.) 2.3 – Troubleshoot Static and Default Routes 2.3.2 – Troubleshoot IPv4 Static and Default Route Configuration 2.3.2.1 – Troubleshoot a Missing Route ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Troubleshoot IPv4 Static and Default Route Configuration Solve a Connectivity Problem A traceroute reveals that R2 forwards the traceroute back to R1. R1 returns it to R2 2.3 – Troubleshoot Static and Default Routes 2.3.2 – Troubleshoot IPv4 Static and Default Route Configuration 2.3.2.2 – Solve a Connectivity Problem ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Troubleshoot IPv4 Static and Default Route Configuration Solve a Connectivity Problem (Cont.) Static route to 192.168.2.0/24 has been configured using the next-hop address 172.16.2.1. Incorrect route is removed and the correct route is then entered 2.3 – Troubleshoot Static and Default Routes 2.3.2 – Troubleshoot IPv4 Static and Default Route Configuration 2.3.2.2 – Solve a Connectivity Problem ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Troubleshoot IPv4 Static and Default Route Configuration Packet Tracer – Troubleshooting Static Routes 2.3 – Troubleshoot Static and Default Routes 2.3.2 – Troubleshoot IPv4 Static and Default Route Configuration 2.3.2.3 – Packet Tracer – Troubleshooting Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Troubleshoot IPv4 Static and Default Route Configuration Lab – Troubleshooting Static Routes 2.3 – Troubleshoot Static and Default Routes 2.3.2 – Troubleshoot IPv4 Static and Default Route Configuration 2.3.2.4 – Lab – Troubleshooting Static Routes ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2.4 Chapter Summary 2 - Static Routing 2.4 – Summary ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential § §Explain how static routes are implemented in a small to medium-sized business network. §Configure static routes to enable connectivity in a small to medium-sized business network. §Troubleshoot static and default route configurations. Conclusion Chapter 2: Static Routing 2.4 – Summary 2.4.1 – Conclusion 2.4.1.2 – Chapter 2: Static Routing ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Section 2.1 New Terms and Commands •stub network •stub router •Standard static route •Summary static route •Floating static route •exit interface • New Terms and Commands ‹#› © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential Section 2.2 New Terms and Commands •next-hop IP address •next-hop static route •directly connected static route •fully specified static route •recursive lookup •link-local address •host route •local host route • New Terms and Commands