catos is organized by function based on three main configuration

8/2/2019 CatOS is Organized by Function Based on Three Main Configuration

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CatOS is organized by function based on three main configuration

commands: show, set, and clear. CatOS function based allows for

easy manipulation of adding and deleting ports from certainfunctions such as EtherChannel, LACPChannel, trunking, vlan

membership, spanning tree function, etc....

CatOS is only for the Cisco Catalyst family of switch; it is only

handling L2 manipulation.

IOS was/is the original Cisco OS which is organized by port. All

configuration is done at the port level rather than at the

function level. Before IOS 11's introduction of the 'range' for

interface configuration, individual ports configuration was amajor pain. (like changing all 384 ports of a Catalyst switch

running IOS to be all switchports in VLAN 5)

Multiple Spanning Tree (MST) to IEEE802.1w Rapid Spanning Tree (RST)

algorithm to multiple spanning tree expansion, which is a virtual LANs

(VLANs) environment provides a rapid convergence and load balancing

features; MST converges faster than PVST + and 802.1D and , 802.1w

Spanning Tree and PVST + compatible structure.

Multi-spanning tree (MST), can trunk (trunks) to create multiple spanning

tree, associated VLANs to spanning tree-related processes,each spanningtree process independent of other process topology; MST provides a

number of data forwarding path and load balancing, and improves

network fault tolerance, because a process (forwarding path) of the

failure will not affect other processes (forwarding path).

In large networks of different network parts to locate through the MST

spanning different VLANs and the distribution process can more easily

manage the network and use redundant paths;a spanning tree process

can only exist in the same VLAN with the process ofdistribution of the

bridge, must use the same MST configuration information to configure a

bridge, which makes them able to participate in a group of bridges

spanning the process, have the same MST configuration information form


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the interconnection of multiple spanning tree bridge (MST) area.

Multiple Spanning Tree (MST) uses modified Rapid Spanning Tree (RSTP)

protocol - called the Multiple Spanning Tree Protocol (MSTP), MST has the

following characteristics:

MST constant running a spanning tree called internal spanning tree

(IST), IST MST region with the increase of general internal information

spanning tree information; MST area for the adjacent single spanning tree

(SST) and MST Region as a separate bridge.

A bridge running MST provides a single spanning tree bridge andinteroperability:

* MST bridges run the internal spanning tree (IST), IST MST region with

the increase of general internal information spanning tree information.

* Internal Spanning Tree (IST) to connect all the MST bridges in the area

and is common spanning tree (CST) of a sub-tree, common spanning tree

(CST) contains the whole of the bridge domain, MST area for the adjacent

single spanning tree (SST ) Bridge and the MST area as a virtual bridge.

* General and internal spanning tree (CIST) is within each MST region

spanning tree (IST), a common interconnection MST area and single

spanning tree bridge spanning a set, it and an MST region is the same as

an IST , it and the CST outside an MST is the same; STP, RSTP and MSTP

together to build a separate bridge to do for the common and internal

spanning tree (CIST) roots.

MST in each district to establish and maintain additional spanning tree,spanning tree is the MST of these processes (MSTIS), IST process number

is 0, MSTIS process number 1,2,3, etc.; even if the MST area are inter-

connected, any MSTI also are local and independent in the MST area to

another area MSTI; MST MST process and the IST in the border area

together constitute CST:


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* MSTI MSTP spanning tree information is contained in the records (M-

record) in, M-record is always encapsulated in the MST's BPDUS in the

original calculation by the MSTP spanning tree, called the M (M-tree), M

tree only MST area active, M trees and IST in the MST region formed CST

border merger

through the generation of non-CST VLAN the PVST + BPDU, MST and

PVST + to provide interoperability

MST supports some of the PVST + extensions:

* UplinkFast and BackboneFast invalid way in the MST, but they are

included in RSTP in* Support PortFast

* BPDUFilter and BPDUGuard supported in MST mode

* LoopGuard and RootGuard supported in MST mode

* For private VLANs (Pvlan), from the main VLANs VLANs must be

mapped to the same spanning tree process.

Understanding Access Control List LoggingContents

Introduction

The log and log-input Access Control Entry Options

Configuring a Log Update Threshold

Limiting ACL LoggingInduced Process Switching

Rate Limiting Syslog Messages

Configuration Example

Optimized ACL Logging

References

Introduction

Logging-enabled access control lists (ACLs) provide insight into traffic as it traverses the network or is dropped

by network devices. Unfortunately, ACL logging can be CPU intensive and can negatively affect other functionsof the network device. There are two primary factors that contribute to the CPU load increase from ACL

logging: process switching of packets that match log-enabled access control entries (ACEs) and the generation

and transmission of log messages. Using the configuration commands detailed in this document, administrators

can strike a balance between traffic visibility and the corresponding impact on device CPU load.

The log and log-input Access Control Entry Options

The log and log-input options apply to an individual ACE and cause packets that match the ACE to be logged.

The log-input option enables logging of the ingress interface and source MAC address in addition to the packet's
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source and destination IP addresses and ports.

The first packet logged via the log orlog-input options will generate a syslog message. There are two scenarios

in which subsequent log messages will not be sent immediately. If the log-enabled ACE matches another packet

with identical characteristics to the packet that generated a log message, the number of packets matched is

incremented and then reported at five-minute intervals. Similarly, if any log-enabled ACE in any ACL on any

interface matches a packet within one second of the initial log message, the match or matches are counted forfive minutes and then reported. These periodic updates will contain the number of packets matched since the

previous message.

The samples below illustrate the initial message and periodic updates sent by an IOS device with a default

configuration using the log ACE option. In the following samples, the first log messages are representative of

those created by an IPv4 ACL; the second log messages are representative of those created by an IPv6 ACL.

*May 1 22:12:13.243: %SEC-6-IPACCESSLOGP: list ACL-IPv4-

E0/0-IN permitted

tcp 192.168.1.3(1024) -> 192.168.2.1(22), 1 packet


E0/0-IN permittedtcp 192.168.1.3(1024) -> 192.168.2.1(22), 9 packets

*May 3 19:05:38.183: %IPV6-6-ACCESSLOGP: list ACL-IPv6-

E0/0-IN/10 permitted

tcp 2001:DB8::3(1027) -> 2001:DB8:1000::1(22), 1 packet



tcp 2001:DB8::3(1027) -> 2001:DB8:1000::1(22), 9 packetsUsing the log-input ACE option causes additional information to be logged. The following log entries are

similar to those shown above; however, they were created using the log-input option and contain the ingress

interface and source MAC address information.


E0/0-IN permitted

tcp 192.168.1.3(1025) (Ethernet0/0 000e.9b5a.9839) ->

192.168.2.1(22), 1 packet


E0/0-IN permitted

tcp 192.168.1.3(1025) (Ethernet0/0 000e.9b5a.9839) ->

192.168.2.1(22), 9 packets

*May 3 19:08:23.027: %IPV6-6-ACCESSLOGP: list ACL-IPv6-E0/0-IN/10 permitted

tcp 2001:DB8::3(1028) (Ethernet0/0 000e.9b5a.9839) ->

2001:DB8:1000::1(22), 1 packet



tcp 2001:DB8::3(1028) (Ethernet0/0 000e.9b5a.9839) ->


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2001:DB8:1000::1(22), 9 packetsThe message identifiers shown above, %SEC-6-IPACCESSLOGPand %IPV6-6-ACCESSLOGP, may vary as a

result of the packets being reported. This variation occurs because diverse types of network traffic have different

characteristics. For example, TCP and UDP have Layer 4 port information and ICMP has type and code

information. The valid identifiers are shown in the following table.

Identifier IPv4 or IPv6

Applicable Protocols

%SEC-6-IPACCESSLOGP

IPv4 TCP (6) and UDP (17)

%SEC-6-IPACCESSLOGSP

IPv4 IGMP (2)

%SEC-6-IPACCESSLOGRP

IPv4 IPinIP (4), GRE (47), EIGRP (88), OSPF (89), NOSIP (94),and PIM (103)

%SEC-6-IPACCESSLOGDP

IPv4 ICMP (1)

%SEC-6-IPACCESSLOGNP

IPv4 Used for all other IPv4 protocols

%IPV6-6-ACCESSLOGP IPv6 TCP (6), UDP (17), and SCTP (132)

%IPV6-6-ACCESSLOGSP

IPv6 TCP (6), UDP (17), SCTP (132), and ICMPv6 (58) withunknown Layer 4 information

%IPV6-6-

ACCESSLOGDP

IPv6 ICMPv6 (58)

%IPV6-6-ACCESSLOGNP

IPv6 Used for all other IPv6 protocols

The list ofIANA Assigned Internet Protocol Numbers is available athttp://www.iana.org/assignments/protocol-

numbers.

Configuring a Log Update Threshold

The ip access-list log-update thresholdthreshold-in-msgs and ipv6 access-list log-update threshold

threshold-in-msgs commands can be used to configure how often syslog messages are generated and sent after

the initial packet match. These commands use a threshold described as a number of packets, not as a timeinterval. This is in contrast to the periodic updates, which are sent every five minutes. A user configurable, time-

based threshold does not presently exist.

This configured threshold is applied per flow and does not disable the initial match log message or the five-

minute periodic update. The log messages in the following example illustrate the interaction of these functions.

These messages were created on a router configured forip access-list log-update threshold 10 and ipv6 access-

list log-update threshold 10 by a 15-packet IPv4 flow and a 15-packet IPv6 flow.
http://www.iana.org/http://www.iana.org/assignments/protocol-numbershttp://www.iana.org/assignments/protocol-numbershttp://www.iana.org/assignments/protocol-numbershttp://www.iana.org/assignments/protocol-numbershttp://www.iana.org/http://www.iana.org/assignments/protocol-numbershttp://www.iana.org/assignments/protocol-numbers


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E0/0-IN permitted

tcp 192.168.1.3(1026) -> 192.168.2.1(80), 1 packet


E0/0-IN permitted

tcp 192.168.1.3(1026) -> 192.168.2.1(80), 10 packets*May 1 23:08:16.127: %SEC-6-IPACCESSLOGP: list ACL-IPv4-

E0/0-IN permitted

tcp 192.168.1.3(1026) -> 192.168.2.1(80), 4 packets



tcp 2001:DB8::3(1029) -> 2001:DB8:1000::1(80), 1 packet



tcp 2001:DB8::3(1029) -> 2001:DB8:1000::1(80), 10packets



tcp 2001:DB8::3(1029) -> 2001:DB8:1000::1(80), 4 packetsThe ip access-list log-update thresholdthreshold-in-msgs command was added to IOS in version 12.0(2)T.

The ipv6 access-list log-update thresholdthreshold-in-msgs command was added to IOS in version 12.2(13)T.

Limiting ACL LoggingInduced Process Switching

The ip access-list logging intervalinterval-in-ms command was released in IOS version 11.3. This command

limits the effects of ACL logginginduced process switching by providing a rate limit for process-switched

packets. The interval configured in the command allows only one packet per interval to be process switched nomatter how many log-enabled ACEs exist. The interval applies globally, and the process switching limit affects

all log-enabled ACEs in all ACLs on all interfaces. Packets that are not process switched will not be examined

and will not be accounted for in logging. This functionality requires Cisco Express Forwarding to be enabled

using the ip cefglobal configuration command.

The ip access-list logging intervalinterval-in-ms command does not apply to logging-enabled IPv6 ACLs and

there is no IPv6 equivalent. As a result, all packets matching log-enabled ACEs in IPv6 ACLs are process

switched.

Administrators can determine the number of packets being process switched using the show interface switching

EXEC command. Although log messages may not be comprehensive after enabling the ip access-list logging

interval command, the counter values displayed using the show access-lists and show ip access-lists commands

are updated properly regardless of the presence or configuration of the ip access-list logging interval command.

Rate Limiting Syslog Messages

The logging rate-limitmessage-rate [exceptseverity-level] command limits the CPU impact of log generation

and transmission. This command applies to all syslog messages and is not exclusive to those created through

ACL logging. Although this command does limit the number of packets that must be generated and sent by the

network device, it does nothing to reduce the number of input packets that are process switched by the device

CPU. For this reason, it is imperative that the ip access-list logging interval command be used in conjunction


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with the logging rate-limit command.

The logging rate-limit command was introduced in IOS 12.1(3)T.

Configuration Example

The following configuration example illustrates the ip access-list logging interval and logging rate-limit

commands as well as logging best practices. The ip access-list logging interval 10 command limits log-induced

process switching to one packet per 10 milliseconds, or 100 packets per second. The logging rate-limit 100

except 4 command in the example limits log generation and transmission to 100 messages per second except for

log levels 4 (warnings) through 0 (emergencies).

!

!-- Configure timestamps for syslog messages with date,

time,

!-- milliseconds, and the time zone configured on the

device.

!service timestamps log datetime msec show-timezone

localtime

!

!-- Enable logging to all enabled destinations.

!

logging on

!

!-- Disable CPU-intensive logging to the console and

terminal.

!no logging console

no logging monitor

!

!-- Configure logging severity level, log buffer size, and

rate

!-- limiting.

!

logging buffered informational

logging buffered 16386

logging rate-limit 100 except 4

!

!-- Configure the host to which syslog messages will be

sent.

!

logging 192.168.1.10

!

!-- Configure the interval between process-switched


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packets.

!

ip access-list logging interval 10

!

Optimized ACL Logging

The Catalyst 6500 series switches and Cisco 7600 series routers include hardware support for ACL logging. This

feature, known as optimized ACL logging (OAL), was added to Cisco IOS Software version 12.2(17d)SXB and

is available on devices that include the Policy Feature Card 3 (PFC3). It should be noted that OAL applies only

to unicast IPv4 packets. All other packet types will be logged in software on the Multilayer Switch Feature Card

(MSFC).To allow OAL to function properly, the mls rate-limit unicast ip icmp unreachable acl-drop 0 global

configuration command must be entered.

More information about OAL is available atOptimized ACL Logging with a PFC3.

References

Logging System Messages

http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_troubleshooting_ps6350_TSD_Products

_Configuration_Guide_Chapter.html#wp1054847

Configuring IP Access Lists

http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtml

IANA Assigned Internet Protocol Numbers

http://www.iana.org/assignments/protocol-numbers

Optimized ACL Logging with a PFC3

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#w

p1090858
http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_troubleshooting_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1054847http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_troubleshooting_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1054847http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtmlhttp://www.iana.org/http://www.iana.org/assignments/protocol-numbershttp://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_troubleshooting_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1054847http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_troubleshooting_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1054847http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtmlhttp://www.iana.org/http://www.iana.org/assignments/protocol-numbershttp://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/acl.html#wp1090858

catos is organized by function based on three main configuration

Documents