Different IOS types, releases and fixes

Transcription

1 Cisco 3825 router with integrated VPN Different IOS types, releases and fixes There are 3 different types of IOS here. There is the standard IOS you have been dealing with in R&S, then there is the IOS XR, a realtime OS designed for the much higher end carrier routing platforms (CRS-1, CRS-3, ASR9000 and XR12000). It is way more stable and is equipped with advanced features such as process mirroring and advanced features. You need to explicitly "commit"in order for a command to make changes. And there is also the IOS XE, which is primarily for the Cisco ASR/Catalyst 4500E platforms. In fact, all the IOS functions in the XE are provided by a daemon named IOSD (officially, in IOS XE the IOS runs as a single daemon within Linux). According to Cisco, IOS XE looks and feels the same as the traditional IOS and there is almost no change in feature configurations. NX-OS is for storage and is more relevant for datacenter operations. 56

2 Fixes for the standard IOS are usually classified into: Maintenance releases, which are heavily tested and highly recommended. Rebuild, which has been constructed from the previous maintenance or major release, has the fix for a specific vulnerability. It receives less testing but it contains minimal changes necessary to effect the repair. Interim releases, which were built at regular intervals between maintenance releases. They also receive less testing and should be selected only when you do not have better alternatives. Before IOS release 15, IOS releases are split into multiple different trains. T is technology train, which gets new features and fixes throughout its life. S is Service Provider train, which is only for the core router products. E is Enterprise train, which is customized for enterprise environments. B is broadband train, which offers many internet based broadband features. Starting with IOS release 15, there is only one train - the M/T train. More on IOS XR and its commands Basic access to physical console and auxiliary port is possible. And there are also dedicated physical management interfaces. For example, on the ASR9000 you can have interface MgntEth0/RSP0/CPU0/0 and MgntEth0/RSP0/CPU0/1. If you need to have IP management access, you should first configure these interfaces with IPs from your management subnet (you may use physical or virtual IPs). In terms of prompt structure, RP means route processor, 0 means single rack chassis (or some other values in a multishelf system), RSP0 or RSP1 means Route Switch Processor (also indicates the slot), CPU0 or CPU1 points to the module, and then there is the router hostname (IOS is the default). 57

3 An ASR 9000 RSP. You do not need to deal with things like startup-config or running-config on IOS XR. To set up things, you first make a collection of changes to the current configuration, then you consider to commit the configuration via the commit You may also use commit best-effort to commit all configuration that can be committed. To commit and add comments together, use commit comment. You may even use commit replace to replace or remove the entire running configuration. If you use the exit command before committing anything, this message will show up: Uncommitted changes found, commit them before exiting(yes/no/cancel)? You use show config to show the uncommitted configuration, or use show config merge to show the expected future configuration after commit. To avoid configuration collisions along the configuration process you can use the configure exclusive command to enter into an exclusive mode which locks out all other users from entering configuration changes. You use sh run int to look into the running config on an interface. To retrieve and show the current system time and interface, use pwd. To switch to a particular interface, use int. To add a new IP address to the current interface, use ip add or ipv6 add. Routing protocol configuration in both IOS and IOS XR are highly similar in concept but a little bit different in syntaxes. 58

4 In terms of RIP: You use auto-summary to enable the automatic summarization of subnet routes into network-level routes. You use broadcast-for-v2 to send output packets to a broadcast address. You use clear rip to clean up entries and statistics. You use clear rip database to clean up only the relevant database entries from the topology table, or use clear rip interface to remove the relevant interface-related information. And you may use clear rip statistics to clear up the relevant statistics. You use default-metric to set the default metric values for routes that are redistributed from other protocols. You use distance to define the administrative distance assigned to routes that have been discovered. You use interface to define the interfaces on which the protocol runs. You use maximum-paths to specify the max number of equal cost parallel routes that can be installed into the routing table. You use neighbor to define the neighboring router with which to exchange protocol information. You use nsf to set up nonstop forwarding after a RIP process shutdown. The main goal of NSF is to continue forwarding packets after route processor switchover (to be precise, a Stateful Switchover). In terms of EIGRP: 59

5 You may enable an IPv4 or IPv6 address family via the address-family You may authenticate EIGRP protocol traffic on interfaces based on the MD5 algorithm via the authentication keychain You may allow the automatic summarization of subnet routes into networklevel routes via the autosummary You may configure the percentage of bandwidth that can be used on an interface, use the bandwidth-percent You may clean up and then re-establish EIGRP neighbor entries via clear eigrp neighbors. To clean up topology entires, use clear eigrp topology. To set the default metrics, you want to use the defaultmetric To use one of the two administrative distances so to provide a better route, you want to use the distance To set the hello interval for a particular interface, you want to use the hellointerval To set the hold time for an interface, you want to use the hold-time To define the interfaces on which the protocol runs, you want to use the interface To define the maximum number of parallel routes to be supported, you want to use the maximum-paths Review Questions: 1, Which OSI layer is responsible for presenting the data in standard formats? 60