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Configuring Network Proximity

Configuring Network Proximity

Network Proximity provides a content delivery solution that significantly improves network performance. This optional software feature uses a Cisco CSS 11150 content services switch (CSS) configured as a database that is populated by actively probing the network to determine the proximity of clients and services. Additional CSSs (any model) perform database lookup requests and domain name resolution to determine the most proximate service for a client.

This chapter describes the Network Proximity feature and provides related configuration information in the following sections:

Entering Your Proximity License Keys

All CSSs include the Standard feature set. If you are upgrading your CSS with the Enhanced feature set or you have purchased the optional Proximity Database software feature, enter the appropriate software license key at the command line using the license command for the optional feature. You will find the option license key on a card in an envelope included in your accessory kit.

Note   If you cannot find the software license key, call the Cisco Technical Assistance Center (TAC) toll free, 24 hours a day, 7 days a week at 1-800-553-2447 or 1-408-526-7209. You can also email TAC at tac@cisco.com.

Proximity Database License Key

Enter the license key for the Proximity Database (PDB) software option on each CSS 11150 with 256 MB of memory that you want to use exclusively as a PDB. For example:

    # license

At the prompt, enter the 12-digit PDB software license key.

    Enter the Software License Key (q to quit):
nnnnnnnnnnnn
Note   After you enter the software license key for the PDB, you must reboot the CSS before you can start using the new feature.

Proximity Domain Name Server License Key

Enter the license key for the Enhanced feature set, which includes the Proximity Domain Name Server (PDNS) feature, on each CSS (any model) that you want to use exclusively as a PDNS. For example:

    # license

At the prompt, enter the 12-digit Enhanced feature set software license key. For example:

    Enter the Software License Key (q to quit):
nnnnnnnnnnnn

Network Proximity Overview

Proximity represents a topological relationship between a client and content services. In a network topology perspective, as used in this chapter, proximity refers to connecting a client to the most proximate service based on a measurement of the round-trip time (RTT) between the client's local DNS server and a proximity zone (refer to Figure 12-1).


Figure 12-1: Simplified Example of Network Proximity


In Figure 12-1, the lowest RTT value is returned from Zone 0. Therefore, Network Proximity would link the client to a service located in Zone 0, regardless of the physical location of the client. The three zones communicate with each other using the Application Peering Protocol (APP). For details on APP, refer to Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

The major components and concepts in Network Proximity are:

Proximity Database

A Proximity Database (PDB) is a dedicated CSS 11150 with 256 MB of memory and is configured as a PDB using the optional Proximity Database software feature. (For details on configuring a CSS 11150 as a PDB, refer to "Configuring the Proximity Database", later in this chapter.) One PDB and one or more Proximity Domain Name Servers (PDNSs) and data centers (server farms or lower-level DNSs) define a subset of the Internet address space called a proximity zone. (For details on proximity zones, refer to "Proximity Zones", later in this chapter.)

Note   A PDB can service up to four PDNSs generating their maximum request rates per zone. If the PDNSs are not fully loaded, you can configure additional PDNSs per zone.

Network Proximity, as implemented on a CSS, uses a topology-testing technique that actively probes clients to determine the relative location of clients and services. To accomplish this, a PDB uses ICMP and TCP requests to actively probe a client's local DNS server for proximity information. The PDB analyzes the probe responses, then stores the resulting network RTT metrics (in milliseconds) in its database.

When a PDNS sends the PDB a proximity lookup request for a client using APP-UDP, the PDB compares the RTT metrics for that client and responds immediately with an ordered zone index, a list of proximity zones in preferred order by RTT. The PDNS then uses the ordered zone index, along with domain name records and keepalive information, to determine the most proximate service for the client.

Note   Probing conducted by the PDB is asynchronous with lookups conducted by the PDNS. Therefore, a PDB will never block a lookup request from a PDNS.

A PDB communicates with PDBs in other zones using a peer mesh, implemented with APP. (For details on APP, refer to Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".) This enables PDBs to periodically "learn" the latest RTT metrics information from the other PDBs in the peer mesh to ensure that a client is connected to the most proximate service. Each PDB contains a metric for every source block of interest in each proximity zone. A source block of interest is a CIDR block that contains a client's local DNS server.

Proximity Domain Name Server

A Proximity Domain Name Server (PDNS) is any CSS that is running the Enhanced feature set and is configured as a PDNS using the Enhanced software feature set. (For details on configuring a CSS as a PDNS, refer to "Configuring the Proximity Domain Name Server", later in this chapter.) A PDNS performs PDB lookup requests, using Application Peering Protocol-User Datagram Protocol (APP-UDP), in response to DNS requests that the PDNS receives from a client's local DNS server. The PDB responds to these lookup requests immediately with the ordered zone index. The PDNS uses the ordered zone index along with domain name records and keepalive information to make an authoritative DNS response to the client's local DNS server.

The primary task of a PDNS is to respond to DNS requests based on proximity and domain availability. However, the CSS is not excluded from supporting local content rules and services, as well as non-Proximity-based DNS load balancing. These non-PDNS activities will affect the CSS's performance as a PDNS and the PDNS activities will affect the CSS's performance as a content services switch, depending on the PDNS's load.

Every proximity zone contains one or more PDNSs, up to a maximum of four generating their maximum request rates per zone. If the PDNSs are not fully loaded, you can configure additional PDNSs in a zone. Each PDNS within a zone acts as an authoritative DNS server for domains representing data centers. A data center can be a server farm attached directly to a CSS or can be a lower-level DNS server (which may or may not be a CSS) representing a server farm. You configure the domains statically on each PDNS.

Each PDNS maintains the following records for the domains configured on it:

A PDNS updates its domain records continually through keepalive messages (using ICMP or APP-UDP) that it sends to its locally configured virtual IP addresses (VIPs) and data centers. The PDNS uses the keepalive responses to track the load (KAL-AP keepalive only, see below) and availability of locally configured domains. Each PDNS in a proximity zone shares its domain information with other PDNSs in each zone using an APP peer mesh (refer to "Peer Mesh", later in this chapter). There is no communication between PDNSs within the same zone, and each PDNS communicates with one PDNS per zone.

For the optional CSS keepalive type (KAL-AP), the keepalive client resides on the PDNS, while the keepalive daemon resides on any CSS-based data center that is the configured recipient of A-records or NS-records as configured on the controlling PDNS. The keepalive daemon extracts the load information of the specified domain names and returns them to the PDNS. This load information originates from:

Proximity Zones

A proximity zone is a logical grouping of network devices that consists of one PDB, one or more PDNSs, and services. Although a zone is really a logical subset of the Ipv4 address space, a zone can also be geographically related to a continent, a country, or a major city. Refer to Figure 12-2.

For example, you can create proximity zones to group geographically distinct network devices. A proximity zone containing data centers in the United States logically groups nodes within a distinct geographical area. Another proximity zone may logically group nodes and data centers in Europe, for example. Zones are numbered beginning with zero.


Figure 12-2: Example of Network Proximity Zones


Peer Mesh

To communicate proximity information between proximity zones, Network Proximity uses APP to create a peer mesh. A peer mesh is an abstraction layer that uses APP to provide common functions (for example, zone configuration information) between Network Proximity devices. A PDB mesh allows PDBs to communicate with one another across proximity zones to share proximity metrics. A PDNS mesh allows a PDNS in one zone to communicate with one other PDNS in each proximity zone to share domain records and keepalive information. For details on APP, refer to Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

Note   You can use the concept of zones with a peer mesh to share domain record information between CSSs acting as DNS servers without the use of a PDB. This configuration allows a scalable method of domain name sharing and the use of NS-records in a non-Proximity-based CSS DNS server environment. For more information, refer to Configuring the CSS Domain Name Service.

Network Proximity Example

Note   A PDB sends ICMP and TCP probes to a client's local DNS server the first time the PDB receives a lookup request for that client from a PDNS. If you configure refinement (refer to "Refining Proximity Metrics", later in this chapter), a PDB will continue to probe that client periodically. Based on the responses it receives from the probes and the information it receives through its peer mesh, a PDB builds and maintains a database of RTT metrics for clients throughout the network. This process is independent of, and asynchronous with respect to, client requests.

The following example illustrates a single point-in-time request from a client. Refer to Figure 12-3 for an illustration of the following steps.

    1. A client performs an HTTP request for the domain name www.home.com.

    2. The local DNS server performs iterative DNS requests to the root server and to the .com server to resolve the domain name into an IP address or refer the client to an authoritative DNS server. (This step is not shown in Figure 12-3.)

    3. The .com server, which is an authoritative DNS server for home.com, has the IP addresses of PDNS-0 and PDNS-1 in its configuration. Both PDNSs are authoritative DNSs for www.work.com. In this example, the .com server refers the local DNS server to PDNS-0 in Zone 0. (Typically, the .com server uses a roundrobin or other load-balancing method to refer local DNS servers to a PDNS. This step is not shown in Figure 12-3.)

Note   Your configuration may include an enterprise DNS server that is positioned between the .com server and the PDNS. The enterprise DNS server would be an authoritative DNS server for home.com. In this case, the enterprise DNS server contains the IP addresses of the PDNSs in its configuration and refers the local DNS server to the appropriate PDNS. In either configuration, the PDNS is authoritative for www.home.com.

    4. The local DNS server forwards the client's request for www.home.com to PDNS-0 in Zone 0.


Figure 12-3: Two-Zone Network Proximity Example


    5. PDNS-0 determines the most proximate zone to send the client to using one of the following scenarios:

    6. If the PDNS determines that the best selection is a name server (NS) record, the PDNS begins a recursive query of the name server to determine an authoritative response. If the PDNS finds that the best selection is an address record (A-record), it formulates an authoritative response immediately. In this example, PDNS-0 decides that the best selection is an A-record (learned through the peer mesh with PDNS-1) for a data center in Zone 1.

    7. The PDNS sends an authoritative response that contains the resolved IP address of www.home.com to the client's local DNS server.

    8. The local DNS server notifies the client that sufficient domain name resolution information is available to establish a data connection to www.home.com.

    9. Lastly, the client uses the local DNS server response information (IP address) to connect to a service in the most proximate zone and starts receiving content. In this example, the most proximate service is located in Proximity Zone 1 at IP address 150.45.6.8.

Note   For details on advanced Network Proximity topics, including tiers and nested zones, refer to "Using Network Proximity Tiers", later in this chapter.

Network Proximity Configuration Quick Start

Table 12-1 and Table 12-2 provide a quick overview of the steps required to configure the PDB and PDNS, respectively. Each step includes the CLI command required to complete the task. For a complete description of each feature and all the command options, refer to the sections following Table 12-1 and Table 12-2.

Proximity Database Configuration Quick Start

Table 12-1 provides an overview of the steps required to configure the PDB. Follow these steps to configure PDB-0 located in Proximity Zone 0 in Figure 12-3. Use the CLI commands outlined in the table to configure basic PDB settings.
Table 12-1: PDB Configuration Quick Start
Task and Command Example

    1. Enter config mode by typing config.

    (config)#

    2. Enable the Application Peering Protocol-User Datagram Protocol (APP-UDP) to allow PDB-0 to communicate with PDNS-0.

    (config)# app-udp

    3. Enable the Application Peering Protocol (APP) to allow PDB-0 to communicate with PDB-1. See Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

    (config)# app

    4. Configure the app session with PDB-1, which is participating in the peer mesh with PDB-0. The IP address you enter is a local interface address on PDB-1. See Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

    (config)# app session 200.16.2.3

    5. Configure PDB-0 in Proximity Zone 0.

    (config)# proximity db 0 tier1 "pdb-usa"

Proximity Domain Name Server Configuration Quick Start

Table 12-2 provides an overview of the steps required to configure PDNS-0 located in Proximity Zone 0 in Figure 12-3. Use the CLI commands outlined in the table to configure basic PDNS settings.
Table 12-2: PDNS Configuration Quick Start
Task and Command Example

    1. Enter config mode by typing config.

    (config)#

    2. Enable APP-UDP to allow PDNS-0 to communicate with PDB-0.

    (config)# app-udp

    3. Enable APP to allow PDNS-0 to communicate with PDNS-1. See Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

    (config)# app

    4. Configure PDNS-0. Specify the proximity zone and tier number, an optional text description, and the IP address associated with PDB-0.

    (config)# dns-server zone 0 tier1 "usa" 172.16.2.2

    5. Configure the CSS to act as a DNS server.

    (config)# dns-server

    6. Configure the app session with PDNS-1 that is participating in the mesh with PDNS-0. The IP address you enter is a local interface address on PDNS-1. See Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

    (config)# app session 200.16.2.5

    7. Create A-records for domains in Zone 0. Specify the domain name mapped to the address record and the IP address bound to the domain name. Include an optional time to live (TTL) value, the number of records to return in a DNS response message, and the keepalive message type.

    (config)# dns-record a www.home.com 123.45.6.7 0 single kal-icmp

    8. Create NS-records for domains on other DNS servers within the proximity zone. Specify the domain name mapped to a domain IP address. Include an optional TTL value, the number of records to return in a DNS response message, and the keepalive message type.

    (config)# dns-record ns www.work.com 123.45.6.8 0 single kal-icmp

    9. Optionally, create content rules for local A-records. In some configurations, there will not be any local content rules or services. For details on creating content rules, see the Content Services Switch Basic Configuration Guide, Configuring the CSS Domain Name Service.

Configuring the Proximity Database

Configure one PDB in each Network Proximity zone you want to create. Once configured, a PDB stores network topology information used to determine the relationship between proximity zones and a client that requests a service. The PDB populates its database through active probing of clients (local DNS servers) and sharing information with PDBs in other zones using an APP mesh. The PDB also responds to lookup requests from each PDNS configured in a zone using APP-UDP.

Note   You must connect a PDB to a PDNS over a reliable link because of the requirements of the APP-UDP-based proximity lookup mechanism.

Configuring a PDB requires the following two tasks:

Optionally, you can configure additional PDB parameters as follows:

Configuring APP-UDP and APP

Network Proximity uses the Application Peering Protocol-User Datagram Protocol (APP-UDP) to exchange proximity information between a PDB and a PDNS, and between a PDNS and services. APP-UDP is a connectionless form of APP.

Note   After you configure APP-UDP, you need to configure APP. APP enables a PDB to exchange zone index information with other PDBs in a peer mesh and a PDNS to exchange address records and keepalive information with other PDNSs in a peer mesh. For information on configuring APP, refer to Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

Configuring APP-UDP requires you to enable APP-UDP.

Optionally, you can configure additional APP-UDP parameters as follows:

Enabling APP-UDP

Use the app-udp command to configure APP-UDP datagram messaging on the PDB and all PDNSs in each zone. This command is available in global configuration mode.

The app-udp command supports the following options:

For example:

    (config)# app-udp

To disable APP-UDP messaging, enter:

    (config)# no app-udp

Securing APP-UDP Datagrams

Use the app-udp secure command to require that all incoming APP-UDP datagrams be encrypted. Encryption prevents unauthorized messages from entering the CSS. This command is used in conjunction with the app-udp options command that specifies secure messages that the CSS accepts.

Caution Using this command without the app-udp options command results in all incoming data being dropped.

The syntax for this global configuration mode command is:

    app-udp secure

The following example illustrates the use of the app-udp secure command. In this example, this configuration allows only incoming traffic from IP address 200.16.2.3 encrypted with the password mysecret. The password is an unquoted text string with a maximum of 31 characters. There is no default.

For example:

    (config)# app-udp
(config)# app-udp secure
(config)# app-udp options 200.16.2.3 encrypt-md5hash mysecret

To restore the default behavior of the CSS to accept all APP-UDP datagrams, enter:

    (config)# no app-udp secure

Specifying APP-UDP Options

Use the app-udp options command to associate APP-UDP options with an IP address. The CSS applies the options to packets sent to the destination address or applies them when the CSS receives datagrams with a matching source IP address. You can configure the IP address to 0.0.0.0 to apply a set of security options to all inbound and outbound datagrams that are not more specifically configured. Using the IP address 0.0.0.0 allows you to set a global security configuration that may be applied to an arbitrary number of peers. This command is available in configuration mode.

The syntax for this global configuration mode command is:

    app-udp options ip_address encrypt-md5hash secret

The app-udp options command contains optional fields that allow you to encrypt datagrams. This encryption method applies to datagrams sent and received over an IP address. Encryption options include:

The following example configures the IP address with the encrypt-md5hash global option. Datagrams sent to or received from 200.16.2.3 are encrypted with the password mysecret. All other datagrams received or transmitted, are subjected to the default encryption secret anothersecret.

For example:

    (config)# app-udp
(config)# app-udp options 200.16.2.3 encrypt-md5hash mysecret
(config)# app-udp options 0.0.0.0 encrypt-md5hash anothersecret

Removing an APP-UDP Options Record

Use the no app-udp options command to remove an options record. This command includes an ip_address option to enable the CSS to associate an IP address with a group of options. Enter the address in dotted-decimal notation (for example, 200.16.2.3).

The syntax for this global configuration mode command is:

    no app-udp options ip_address

For example:

    (config)# no app-udp options 200.16.2.3

Specifying the APP-UDP Port

Use the app-udp port command to set the UDP port number that listens for APP-UDP datagrams. The app-udp port command includes the port_number variable, which specifies the UDP port number. Enter a value of 0 to 65535. The default is 5002.

The syntax for this global configuration mode command is: 

    app-udp port port_number

For example:

    (config)# app-udp port 2

To restore the UDP port number to its default value of 5002, enter:

    (config)# no app-udp port
Note   Now that you have configured APP-UDP, you must configure APP as described in Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol", to enable PDB and PDNS peer meshes.

Showing APP-UDP Configurations

Use the show app-udp command to display APP-UDP global statistical information and security configuration settings.

The options for the show app-udp command are:

For example, to display statistical information about the operation of APP-UDP, enter:

    (config)# show app-udp global

Table 12-3 describes the fields in the show app-udp display.
Table 12-3: Show APP-UDP Global Display FIelds
Field Description

Transmit Frames

The number of frames transmitted through APP-UDP

Transmit Bytes

The number of bytes transmitted through APP-UDP

Transmit Errors

The number of frames dropped because of transmit resource errors

Receive Frames

The number of frames received through APP-UDP

Receive Bytes

The number of bytes received through APP-UDP

Receive Errors

The number of frames dropped because of security mismatches

For example, to display the current security configuration settings for APP-UDP, enter:

    (config)# show app-udp secure

Table 12-4 describes the fields in the show app-udp secure display.


Table 12-4: Show APP-UDP Secure Display Fields
Field Description

IP Address

The IP address associated with the APP-UDP security option

Type

The MD5 hashing method used for datagram encryption

Secret

The string used in the encryption and decryption of the MD5 hashing method

Enabling the Proximity Database

Note   Before you enable the PDB, you must configure APP-UDP and APP. For details on configuring APP-UDP, refer to "Configuring APP-UDP and APP", earlier in this chapter. For details on configuring APP, refer to Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

Use the proximity db command to enable the PDB on the CSS.

Note   Once you have enabled APP-UDP and APP, proximity db is the only command that is required to use the PDB. Other PDB commands are optional, but recommended, depending on your application. For details, refer to each command description in the next sections.

The syntax for this global configuration mode command is:

    proximity db zoneIndex {tier1|tier2} {"description"}}

The proximity db command supports the following variables and options:

For example:

    (config)# proximity db 1 tier1 "pdb-usa"

To disable the Proximity Database, enter:

    (config)# no proximity db

Assigning Proximity Metrics

Use the proximity assign command to provide a local metric or to provide metrics (in milliseconds) for all proximity zones. The proximity assign command overrides the default metric determination processes. This command allows you to turn off probe traffic to Classless Inter-Domain Routing (CIDR) blocks.

When you use this command, Network Proximity does not perform active probing of the assigned block. Assigned information is shared with all PDBs in the PDB mesh. You can use this Network Proximity command only on a PDB.

Note   The proximity assign command is not added to the running-config.

The syntax for this SuperUser configuration mode command is:

    proximity assign ip_address ip_prefix ["local_metric"|"metric_list"]

This command supports the following variables:

For example, the following command uses the local_metric variable to assign a value of 200 to all client DNS addresses included in the range 172.23.5.7/24.

    # proximity assign 172.23.5.7/24 "200"

This command uses the metric_list variable to assign a value of 200 ms to proximity zone 0, does not configure zone 1 (specified by a value of zero), and assigns a value of 50 ms to zone 2.

    # proximity assign 172.23.5.7/24 "200 0 50"

Flushing Proximity Assignments

Use the proximity assign flush command to remove existing proximity assignments configured with the proximity assign command. You can use this Network Proximity command only on a PDB.

Note   Using the proximity assign flush command without additional syntax removes all proximity assignments.

The syntax for this SuperUser configuration mode command is:

    proximity assign flush {ip_address ip_prefix}

The proximity assign flush command supports the following variables:

For example:

    # proximity assign flush 172.23.5.7/24

Configuring Proximity Time to Live

Use the proximity ttl command to set the TTL value, in minutes, for each PDB response. This value tells the PDNS how long to cache the PDB response. You can use this Network Proximity command only on a PDB.

The syntax for this global configuration mode command is:

    proximity ttl assigned | probe minutes

The options for this global configuration mode command are:

For example:

    (config)# proximity ttl assigned 25

To reset the TTL value to its default, enter:

    (config)# no proximity ttl probe
Note   A TTL value of 255 never ages out the entries.

Storing the Proximity Database

Use the proximity commit command to write a portion or all of the proximity database to a file in the log directory on the CSS disk or to a file on an FTP server. This command is useful for exporting the database so that you can view, modify, or recover information in the PDB. The database output contains metrics for all proximity zones, the current advertisement state, and hit counts.

To retrieve the database log file, use the proximity retrieve command. You can use this Network Proximity command only on a PDB.

By default, when you enter this command without any of its options, it writes the entire database to an XML-formatted file named proximity.db in the log directory on the CSS disk. You can optionally specify that the database be encoded using compact binary encoding. You can also specify that the database be written to a file on an FTP server.

The syntax for this SuperUser command is:

    proximity commit {ip_address ip_prefix|entire-db {ftp ftp_record ftp_filename {bin}|log filename {bin}}}

The proximity commit command supports the following variables and options:

Note   An XML database occupies approximately three times the space a binary-encoded database occupies. However, a binary encoded database cannot be viewed.

For example:

    # proximity commit 172.23.5.7/24 xml

Retrieving the Proximity Database

Use the proximity retrieve command to load a PDB from disk or an FTP server. Proximity metrics loaded from the database file replace any overlapping entries existing in the database and supplement any non-overlapping database entries. You can use this Network Proximity command only on a PDB.

Note   If you enter the proximity retrieve command without any of its options, the CSS loads the file proximity.db from disk by default.

The proximity retrieve command distinguishes between XML encoded and binary database formats automatically.

The syntax for this SuperUser command is:

    proximity retrieve {ftp ftp_recordname ftp ftp_filename|log filename}

The proximity retrieve command supports the following variables:

For example:

    # proximity retrieve ftp proxconfig proxconfignew

Refining Proximity Metrics

Use the proximity refine and the proximity refine once commands to initiate the continuous or single refinement, respectively, of metric entries in the PDB. Refinement updates the metric entries for all clients in the database to reflect conditions that exist at a particular point in time. You can use these Network Proximity commands only on a PDB.

When you issue the proximity refine command, the PDB probes all existing clients in the database periodically based on the size of the database and the database hit counts for the clients. The PDB organizes clients into three groups by hit count: N1, N2, and N3. The PDB probes N1 more frequently than N2, and N2 more frequently than N3. The percentage of time spent probing N1, N2, and N3 is approximately 45%, 35%, and 20%, respectively.

When you issue the proximity refine once command, the PDB probes all existing clients in the database only once.

The syntax and options for these SuperUser configuration mode commands are:

    # proximity refine
# proximity refine once

To stop a refinement in progress, enter:

    # no proximity refine

Using Proximity Reprobe

Use the proximity reprobe command to send additional probes to existing IP addresses in the proximity database once. You can use this Network Proximity command only on a PDB. You can use the proximity reprobe command with the proximity refine commands.

Note   IP addresses configured with the proximity assign command are not eligible for reprobing.

The syntax for this SuperUser configuration mode command is:

    proximity reprobe ip_address {ip_prefix}

The proximity reprobe command supports the following variables:

For example:

    # proximity reprobe 172.23.5.7/24

Clearing the Proximity Database

Use the proximity clear command to remove entries from the proximity database.

Caution Be sure you want to permanently delete entries in the PDB before you use this command. Using the proximity clear command without optional variables permanently removes all entries in the proximity database.

The syntax for this SuperUser command is:

    proximity clear ip_address ip_prefix

The proximity clear command supports the following variables:

Configuring the Proximity Probe Module

The Proximity Probe Module is responsible for sending ICMP and TCP probes to clients based on PDNS lookup requests to the PDB and refinement settings. Refer to the following sections to configure the Proximity Probe Module:

Configuring the Proximity Probe Module Method

Use the proximity probe rtt method command to configure the primary and secondary methods used for proximity metric discovery. You can use this Network Proximity command only on a PDB.

The syntax for this global configuration mode command is:

    proximity probe rtt method [icmp {tcp}|tcp {icmp}]

The proximity probe rtt method command supports the following options:

For example:

    (config)# proximity rtt method icmp

Specifying the Proximity Probe Module Samples

Use the proximity probe rtt samples command to configure the number of ICMP requests to send for each client probe. You can use this Network Proximity command only on a PDB.

Note   Because only one TCP SYN request is sent, you cannot configure this command for TCP probes.

The syntax for this global configuration mode command is:

    proximity probe rtt samples number

The number variable specifies the default number of ICMP echo requests used for averaging during an initial probe. Enter a number from 1 to 30. The default is 2.

For example:

    (config)# proximity probe rtt samples 5

To reset the number of ICMP echo requests to its default value of 2, enter:

    (config)# no proximity probe rtt samples

Configuring the Proximity Probe Module Metric Weighting

Use the proximity probe rtt metric-weighting command to configure the percentage of the previously stored metric value in the database that is used to determine the new metric value. This command allows the PDB to smooth network metric variation caused by network congestion, flash crowds, and so on. You can use this Network Proximity command only on a PDB.

The syntax for this global configuration mode command is:

    proximity probe rtt metric-weighting number

The number variable specifies the percentage of the previous metric value used. Enter a number from 0 to 99. The default is 0.

For example:

    (config)# proximity probe rtt metric-weighting 10

For this example, suppose the previously stored metric value for a client's local DNS server is 40 and the current metric value is 50. If you issue the command above, the PDB adds 10% of the previous metric value (0.10 x 40) to 90% of the current metric value (0.90 x 50) to determine the new metric value. So, the new metric value would be 49. A number value of 50 causes the PDB to average the previous and current metric values.

To reset this command to its default value of 0, enter:

    (config)# no proximity probe rtt metric-weighting

Configuring the Proximity Probe Module Interval

Use the proximity probe rtt interval command to configure the delay in seconds between ICMP samples. You can use this Network Proximity command only on a PDB.

The syntax for this global configuration mode command is:

    proximity probe rtt interval seconds

The seconds variable identifies the length of time (in seconds) to wait between ICMP samples. Use a range between 1 to 10. The default is 1.

For example:

    (config)# proximity probe rtt interval 5

To reset the delay between samples to its default value of 1 second, enter:

    (config)# no proximity probe rtt interval

Specifying Proximity Probe Module TCP-ports

Use the proximity probe rtt tcp-ports command to configure the probe ports for TCP proximity metric discovery. You can use this Network Proximity command only on a PDB.

The syntax for this global configuration mode command is:

    proximity probe rtt tcp-ports port_number1 {port_number2 {port_number3 {port_number4}}}

Define the port number to be tried, in order of precedence. Enter a number from 1 to 65535 to enable a port. The defaults for the various port numbers include:

Note   Ports that you do not specify default to 0.

To reset the probe ports to their default values, enter:

    (config)# no proximity probe rtt tcp-ports

Using Network Proximity Tiers

The following sections describe the advanced Network Proximity concept of tiers. Network Proximity uses tiers to further expand the proximity architecture by allowing you to create more distinct network zones and subzones.

Proximity Tiers

Sharing information among multiple PDBs may result in the management of a very large data set. As you add more proximity zones to the network, Network Proximity scales to provide more distinct network zones, allowing zones or subzones to exist within other zones. Network Proximity treats these zones as:

Note   You can configure six Level 1 proximity zones and 16 Level 2 proximity zones. A Level 1 tier supports up to 2 million unique local DNS server addresses. A Level 2 tier supports slightly less than one million unique local DNS server addresses.

In a tiered Network Proximity model, the owner of the name server record is a nested PDNS that is communicating with a nested PDB located within the Level 2 proximity subzone.

Tiered Network Proximity Example

In Figure 12-4, a two-tiered configuration example illustrates how you can use tiers to group more specific network proximity zones. The proximity zone that encompasses all network devices within the United States is broken down further to include an additional tier that comprises the more specific geographical proximity zones, East Coast and West Coast.

By adding a tier to this configuration, the capacity of Network Proximity is extended by creating two subzones (Zones 0.1 and 0.2) that include additional PDBs, PDNSs, and data centers. In this way, you can scale Network Proximity to meet your users' needs with increased proximity specificity and thereby increase network performance.

The following steps describe how Network Proximity determines the most proximate service for a client requesting the domain www.work.com. Refer to Figure 12-4.

    1. The client performs an HTTP request for the domain name www.work.com.

    2. The client's DNS server performs iterative DNS requests to the root server and to the .com server to start resolving the domain name into an IP address. (This step is not shown in Figure 12-4.)

    3. The .com server, which is an authoritative DNS for work.com, has the IP addresses of PDNS-0 and PDNS-1 in its configuration. The Level 1 PDNSs are authoritative DNSs for www.work.com. In this example, the .com server refers the client's DNS server to PDNS-0 in Zone 0. (Typically, the .com server uses a roundrobin or other load-balancing method to refer local DNS servers to a PDNS. This step is not shown in Figure 12-4.)

Note   Your configuration may include an enterprise DNS server that is positioned between the .com server and the PDNSs. The enterprise DNS server would be an authoritative DNS server for work.com. In this case, the enterprise DNS server contains the IP addresses of the PDNSs in its configuration and refers the local DNS server to the appropriate PDNS. In either configuration, the PDNS is authoritative for www.work.com.

    4. The local DNS server forwards the client's request for www.work.com to PDNS-0 in Zone 0.

    5. PDNS-0 determines the most proximate zone to send the client to using one of the following scenarios:


Figure 12-4: Tiered Network Proximity Configuration


    6. If the PDNS determines that the best selection is a name server (NS) record, the PDNS begins a recursive query of the name server to determine an authoritative response. If the PDNS finds that the best selection is an address record (A-record), it formulates an authoritative response immediately. In this example, PDNS-0 decides that the best selection is a name server (NS) record for PDNS-0.1 in Zone 0.1.

    7. PDNS-0.1 uses the same logic outlined in steps 5 and 6 above to determine the most proximate service for the client. In this example, PDNS-0.1 decides that the best selection is an address record (A-record) for one of its attached data centers. PDNS-0.1 then makes an authoritative response to PDNS-0 with the A-record for the data center that contains www.work.com.

    8. PDNS-0 sends an authoritative response that contains the resolved IP address of www.work.com to the client's local DNS server.

    9. The client's DNS server notifies the client that sufficient domain name resolution information is available to establish a data connection to www.work.com.

    10. Lastly, the client uses the resolved IP address to connect to a service in the most proximate zone and starts receiving content. In this example, the most proximate service is located in Proximity Zone 0.1 (East Coast) at IP address 123.45.6.9.

Displaying Proximity Database Configurations

The CSS provides a comprehensive set of Network Proximity show commands that display information about the PDB. Use the show proximity command to display PDB configuration or session information. Refer to the following sections for information on using Proximity Database show commands:

Showing the Proximity Database

Use the show proximity command to display an activity summary of the proximity database. This command functions only on a PDB.

For example:

    # show proximity

Table 12-5 describes fields for the show proximity command display.
Table 12-5: Show Proximity Display Fields
Field Description

Lookups

The total number of resolved proximity requests

Lookup Rate

The number of resolved proximity requests per second averaged over the past three seconds

Probe TTL

The configured time-to-live value for client addresses that are probed

Assigned TTL

The configured time-to-live value for client addresses that are assigned to the PDB

Assigned Blocks

Number of blocks in the PDB that are assigned

Probed Blocks

Number of blocks in the PDB that are probed

Total Blocks

Total number of blocks in the PDB

Last Retrieve

The last time that a proximity retrieve was executed

Last Commit

The last time that a proximity commit was executed

DB Utilization

Percentage of the PDB used

Refinement

Specifies whether or not refinement is enabled

Total Peers

The total number of peers in the PDB mesh

Note   All database values are cleared when you reboot the CSS or you issue the no proximity db command.

Showing Proximity Metrics

Use the show proximity metric command to display metrics (in milliseconds) associated with client IP addresses. This command is available on a PDNS and a PDB.

The syntax and options for this global configuration mode command are:

    show proximity metric ip_address {ip_prefix {aggregate}}
Note   Probed metrics are statistically aggregated at the /8 and /16 prefix levels.

For example, to view the proximity metrics associated with the client IP address of 172.23.5.7 and an IP prefix of 24, enter:

    (config)# show proximity metric 172.23.5.7/24

In the PDB, the RTT metrics are sorted by proximity zone. In the PDNS, the metrics are sorted by RTT. An asterisk next to a zone indicates the zone where the command was issued.

Note   The maximum value of an RTT metric is 3968 ms. A value of 4095 ms indicates that a client's local name server was unreachable or had an RTT value of more than 4 seconds.

Table 12-6 describes fields for the show proximity metric command display.
Table 12-6: Show Proximity Metric Display Fields
Field Description

Index

The local zone index number associated with the PDNS proximity zone. The * indicates the local proximity zone where you issued this command.

Description

A text description of the proximity zone that associates a logical name description with the proximity zone as entered with the proximity db or the dns-server zone command.

Metric (RTT)

Round-trip time (RTT) between the PDB and a client's local DNS server. This value (in milliseconds) is the proximity metric for load-balancing decisions.

Showing Proximity Statistics

Use the show proximity statistics command to display statistics associated with client IP addresses. This Network Proximity command is only availabe on the PDB.

The syntax and options for this global configuration mode command are:

    show proximity statistics ip_address {ip_prefix {aggregate}}

For example, to view the proximity statistics associated with the client IP address of 10.1.0.0 and an IP prefix of 16, enter:

    (config)# show proximity statistics 10.1.0.0/16

Table 12-7 describes fields for the show proximity statistics command display.
Table 12-7: Show Proximity Statistics Display Fields
Field Description

IP/Prefix

The IP address and prefix associated with the statistics display.

Lookup Count

The number of times a lookup request from a PDNS was resolved to this IP/Prefix pair.

Showing Proximity Refinement

Use the show proximity refine command to display information pertaining to entries being refined in the PDB. This Network Proximity command is only available on a PDB. For an explanation of the N1, N2, and N3 groups mentioned below, refer to "Refining Proximity Metrics", earlier in this chapter.

For example:

    (config)# show proximity refine

Table 12-8 describes fields for the show proximity refine command display.
Table 12-8: Show Proximity Refine Display Fields
Field Description

N1 - 3 Count

The number of entries in each N grouping.

N1 - 3 Percent

Of all entries, the percentage of entries in the N grouping.

N1 - 3 Rate

The average number of refinement probes per second.

N1 - 3 Probed

The total number of probes since the proximity refine command was invoked.

N1 - 3 Cycle Time

The amount of time to cycle through the N count.

Aggregate Count

The total count for N1 through N3.

Aggregate Probed

The probed total for N1 through N3.

Aggregate Rate

The rate total for N1 through N3.

Showing Proximity Assignments

Use the show proximity assign command to display the user-assigned metric values (in milliseconds) of all proximity zones or for a configured IP address range.

The syntax and variables for this global configuration mode command are:

    show proximity assign {ip_address ip_prefix}

For example, to view the metric assignments for all IP addresses within the range of 200.16.0.0 to 200.16.255.255, enter:

    (config)# show proximity assign 172.23.5.7/16

Table 12-9 describes the fields in the show proximity assign screen.
Table 12-9: Show Proximity Assign Display Fields
Field Description

IP/Prefix

The assigned IP addresses and their associated IP prefixes.

Hits

The total number of hits.

Zone Metrics

The metrics (in milliseconds) that were assigned using the proximity assign command.

Showing Proximity Zones

Use the show proximity zone command to view the state information for each proximity zone, excluding the local proximity zone. This command is similar to the show zone command for the PDNS; however, the show proximity zone command provides information from the perspective of the PDB. This Network Proximity command is available only on a PDB.

The syntax for this global configuration mode command is:

    show proximity zone {number}

Use the number variable to display the state information for a specific proximity zone. Enter a zone number from 0 to 15.

For example, to display the state information for proximity zone 1, enter:

    (config)# show proximity zone 1

Table 12-10 describes the fields in the show proximity zone screen.
Table 12-10: Show Proximity Zone Display Fields
Field Description

Index

The local index number associated with the PDNS proximity zone.

Description

A text description of the proximity zone that associates a logical name description with the proximity zone as entered with the proximity db command.

IP Address

The IP address used for PDB communication with the proximity zone peer.

State

The state of the PDB connection with the peer:

Initializing - The PDB state connection is initializing.

Sync - The PDB state connection is synchronizing with the peer.

Normal - The PDB state connection is normal.

Illegal - The PDB state is an illegal connection.

UpTime

Elapsed time since the proximity db command was executed locally, or since the peer entered the APP mesh.

Showing Proximity Zone Statistics

The show proximity zone statistics command displays information about the APP peer mesh blocks sent and received for a peer for all proximity zones.

The syntax for this global configuration mode command is:

    show proximity zone statistics {number}

Use the number variable to display statistics for a specific proximity zone. Enter a zone number from 0 to 15.

For example, to display the peer block information for zone 1, enter:

    (config)# show proximity zone statistics 1

Table 12-11 describes the fields in the show proximity zone statistics display.
Table 12-11: Show Proximity Zone Statistics Display Fields
Field Description

Index

The local index number associated with the proximity zone.

Description

A text description of the proximity zone that associates a logical name description with the proximity zone as entered with the proximity db command.

Sent

The number of blocks sent to the peer.

Received

The number of blocks received from the peer.

Last Update

The last time information was exchanged between the local PDB and the peer in either direction.

Showing Proximity Probe Module Statistics

Use the show proximity probe rtt statistics command to view the Round Trip Time (RTT) probe module statistics.

The syntax for this global configuration mode command is:

    show proximity probe rtt statistics

For example:

    (config)# show proximity probe rtt statistics

Table 12-12 describes the fields in the show proximity probe rtt statistics screen.
Table 12-12: Show Proximity Probe RTT Statistics Display Fields
Field Description

Total Client Probes

The total number of times that the PDB has probed a client to measure the RTT value. This may be more than the total number of unique clients and may be less than the actual number of ICMP or TCP requests.

Average Probes/minute

The cumulative average number of probes per minute since the PDB was last reset.

ICMP requests sent

The total number of ICMP requests that have been successfully sent from the PDB in order to measure the RTT value.

ICMP responses

The total number of ICMP responses that the PDB has received. Valid ICMP responses are used to measure the RTT.

ICMP failures

The total number of ICMP requests that were successfully sent but did not receive a reply. The ICMP probe requests that do not receive a response are not used to measure the RTT value.

Average ICMP requests/minute

The cumulative average number of ICMP requests per minute since the PDB was last reset.

ICMP send failures

The total number of ICMP requests that the PDB tried to send but failed internally due to a missing route or other problem.

TCP requests sent

The total number of TCP requests that have been successfully sent from the PDB in order to measure the RTT value.

TCP responses

The total number of TCP responses that the PDB has received. Valid TCP responses are used to measure the RTT value.

TCP failures

The total number of failed TCP requests destined for a port on the client's local name server.

Average TCP requests/minute

The cumulative average number of TCP requests per minute that were successfully sent during the time period since the PDB was last reset.

TCP send failures

The total number of TCP requests that the PDB tried to send but failed internally due to a missing route or other problem.

Configuring the Proximity Domain Name Server

The Proximity Domain Name Server (PDNS) is an authoritative DNS that uses information from the Proximity Database (PDB) to resolve DNS requests based on an ordered zone index. As an authoritative DNS, the PDNS uses domain records to map a given domain to an IP address or to a lower-level DNS. You can configure a total of 1024 unique domain names for all PDNSs in a proximity mesh per proximity level. The same domain names can appear in all zones and on multiple PDNSs within a zone.

Note   You must connect a PDNS to a PDB over a reliable link due to the requirements of the APP-UDP-based proximity lookup mechanism.

Configuring a PDNS involves the following required tasks:

Optionally, you can perform the following PDNS-related tasks:

Configuring APP-UDP and APP

Network Proximity uses the Application Peering Protocol-User Datagram Protocol (APP-UDP) to exchange proximity information between a PDB and a PDNS, and between a PDNS and services. APP-UDP is a connectionless form of the Application Peering Protocol (APP). For details, refer to "Configuring APP-UDP and APP", earlier in this chapter.

Note   In addition to configuring APP-UDP, you need to configure APP. APP enables a PDB and a PDNS to exchange proximity information with their peers. For information on configuring APP, refer to See Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

Enabling the Proximity Domain Name Server

Note   Before you enable the PDNS, you must configure APP-UDP and APP. For details on configuring APP-UDP, refer to "Configuring APP-UDP and APP", earlier in this chapter. For details on configuring APP, refer to Configuring the CSS Domain Name Service, in the section "Configuring Application Peering Protocol".

Use the dns-server zone and dns-server commands to enable the PDNS. The syntax for this global configuration mode command is:

    dns-server zone zone_index {tier1|tier2 {"description" {ip_address}}}

The dns-server zone command supports the following variables and options:

For example:

    (config)# dns-server zone 1 tier1 "pdns-usa" 172.16.2.2

Configuring Domain Records

Use the dns-record command and its options to create a domain record on the PDNS. The PDNS uses two types of domain records to map a domain name to an IP address or to another DNS server:

Configuring A-Records

Use the dns-record a command to create a domain A-record on the PDNS that maps the domain name to an IP address.

The syntax for this global configuration mode command is:

    dns-record a dns_name ip_address {ttl_value {single|multiple {kal-ap|kal-icmp|kal-none {ip_address2 {threshold}}}}

The dns-record a command supports the following variables and options:

Note   To use kal-ap proximity keepalive messages, lower-level CSSs acting as either data centers or DNS servers must be running the Enhanced feature set. When the PDNS is directly attached to a server farm, an internal keepalive is used.

For example:

    (config)# dns-record a www.home.com 123.45.6.7 15 single kal-icmp

Domain records include optional keepalive message functionality. The default keepalive message is ICMP. Keepalive messaging options include:

For example:

    (config)# dns-server a www.home.com 123.45.6.7 15 single kal-ap 123.45.6.12 100

Configuring NS-Records

Use the dns-record ns command to create a domain record on the PDNS that maps the domain name to the IP address of a lower-level DNS server.

The syntax for this global configuration mode command is:

    dns-record ns dns_name ip_address {ttl_value {single|multiple {kal-ap|kal-icmp|kal-none {ip_address2 {threshold}}}}

The dns-record ns command supports the following options:

Note   To use kal-ap proximity keepalive messages, lower level CSSs acting as either data centers or DNS servers must be running the Enhanced feature set. When the PDNS is directly attached to a server farm, an internal keepalive is used.

For example:

    (config)# dns-record ns www.work.com 123.45.6.8 15 single kal-icmp

The DNS domain record includes optional keepalive messaging functionality. The default keepalive message is ICMP. Keepalive messaging options include:

For example:

    (config)# dns-server ns www.work.com 123.45.6.8 15 single kal-ap 123.45.6.20 100

Removing a Domain Record

Use the no dns-record command to remove a domain record.

The syntax for this global configuration mode command is:

    no dns-record dns_name

The dns_name variable maps the DNS name to the address record. Enter the name as a case-sensitive unquoted text string with no spaces and a maximum length of 32 characters.

For example:

    (config)# no dns-record www.home.com

Disabling the Proximity Domain Name Server

Use the no dns-server zone command to disable the PDNS Proximity functions by removing the dns-server zone command configuration. Disabling the PDNS prevents it from submitting proximity metric lookup requests to the PDB, and stops the peer mesh communications and record keepalive processing. After issuing the no dns-server zone command, you can still use the PDNS as a DNS server.

For example:

    (config)# no dns-server zone
Note   Before you can issue this command, you must issue the no dns-server command. The no dns-server command also disables the Network Proximity functions and DNS server functions on the PDNS. Because this command does not delete the dns-server zone command configuration, you may want to use the no dns-server command to disable a PDNS temporarily.

Clearing the DNS Server Statistics

Use the dns-server zero command in global configuration mode to set the DNS server request and response statistics displayed by the show dns-server command to zero.

For example:

    (config)# dns-server zero

Enabling the Proximity Lookup Cache

Use the proximity cache-size command to modify the size of the proximity lookup cache. The PDNS uses the proximity lookup cache to store PDB responses. The proximity lookup cache allows the PDNS to resolve proximity decisions faster by allowing a local lookup.

Note   The proximity cache is limited to 48,000 entries.

The syntax for this global configuration mode command is:

    proximity cache-size cache_size

The proximity cache-size command includes a cache size variable that specifies the size of the proximity lookup cache. Enter a value between 0 and 48,000. Entering a value of 0 disables the proximity lookup cache. Modifying the cache size results in flushing the existing entries. The default cache size is 16,000.

For example:

    (config)# proximity cache-size 30000

To restore the default cache size (16,000 entries), enter:

    (config)# no proximity cache-size

Removing Entries from the Proximity Lookup Cache

Use the proximity cache-remove command to remove entries from the proximity lookup cache. The prefix length parameter allows you to remove multiple entries in a single operation. This Network Proximity command can be used only on a PDNS.

The syntax for this SuperUser configuration mode command is:

    proximity cache-remove ip_address ip_prefix|all
Note   If you specify all, you cannot specify an ip_address or ip_prefix value.

The proximity cache-remove command supports the following variables and option:

For example:

    # proximity cache-remove 150.45.6.10 /24

Displaying Proximity Domain Name Server Configurations

The CSS CLI provides a comprehensive set of Network Proximity show commands that display proximity configurations. Refer to the following sections for information on using PDNS show commands:

Showing the Proximity Cache

Use the show proximity cache command to display the current state of the proximity lookup cache. This display provides information about the current cache configuration, entries present, number of hits, and so on. This command is available only on the PDNS.

The syntax and options for this global configuration command are:

    show proximity cache {all|ip_address ip_prefix}

For example:

    (config)# show proximity cache

Table 12-13 describes the fields in the show proximity cache screen.
Table 12-13: Show Proximity Cache Display Fields
Field Description

Maximum Entries

The maximum number of entries the cache supports

Used Entries

The number of entries used by the cache

Free Entries

The number of free entries in the caches

Percent Available

The available percentage of unused cache

Hits

The number of cache lookup hits

Misses

The number of cache lookup misses

Percent Hits

The percentage of cache lookup hits

To display all information pertaining to the proximity cache, enter:

    (config)# show proximity cache all

Table 12-14 describes the fields in the show proximity cache all screen.
Table 12-14: Show Proximity Cache All Display Fields
Field Description

IP/Prefix

The IP address in the cache and the IP prefix associated with the IP address.

Hits

The total number of hits the cache received.

Descending Zone Proximity

Indices of desirable zones ordered by proximity to the client.

TTL

The TTL value associated with the cache entry. The "N" in the second row tells the PDNS to never age out the entries in the cache and is enabled by a TTL value of 255.

Showing DNS-Record Statistics

Use the show dns-record statistics command to display statistics associated with the address records (A-records) or name server records (NS-records) configured locally and learned by the CSS from its peers.

The syntax for this global configuration mode command is:

    show dns-record statistics {domain_name}

You may enter an optional domain name target to display content. If you omit the domain name, all domains appear.

For example:

    (config)# show dns-record statistics

Table 12-15 describes the fields in the show dns-record statistics screen.
Table 12-15: Show DNS-Record Statistics Display Fields
Field Description

<domain_name>

The name of the domain whose DNS records appear.

Local

The state of the local domain record.

Zone Count

The number of zones where the domain record is configured.

Zone

The zone number corresponding to the DNS record. A value of 255 indicates that the record never came up. An asterisk (*) indicates the local zone from where the command was issued.

Description

The description of the zone, as entered with the dns-server zone command.

Type

The DNS record type:

  • A indicates an address record

  • NS indicates a name-server record

IP Address

The configured IP address for the zone.

TTL

Time to Live, indicates how long the receiver of a DNS reply for the given domain should cache the address information. By default, the TTL value is 0, which indicates that the name server receiving the response should not cache it.

Hits

The number of times this record-zone pair was returned in response to a DNS lookup.

Showing DNS-Record Keepalives

Use the show dns-record keepalive command to display information about keepalives associated with DNS records.

The syntax for this global configuration command is:

    show dns-record keepalive {domain_name}

You may enter an optional domain name target to display content. If omitted, all DNS records appear.

For example:

    (config)# show dns-record keepalive

Table 12-16 describes the fields in the show dns-record keepalive screen.
Table 12-16: Show DNS-Record Keepalive Display Fields
Field Description

Name

The domain name for the record.

Type

The keepalive message type for this record: AP, ICMP, or none.

IP Address

Destination IP address of the keepalive message.

State

The state of the record, either UP or DOWN.

Load

The load for the record. This field is used with Threshold and applies only to an AP record type. If the load value exceeds the threshold value, the PDNS removes the DNS record from eligibility.

Transitions

The number of state transitions.

Threshold

The configured load threshold for the record. This field applies only to an AP record type. If the load value exceeds the threshold value, the PDNS removes the DNS record from eligibility.

Showing Server Zones

Use the show zone command to display information about proximity zones communicating with a CSS Network Proximity service.

The syntax for this global configuration command is:

    show zone {zone {verbose} | local | verbose}

The variable and options for this command are:

For example:

    (config)# show zone

To display proximity zones, including a count of transmitted and received client packet types, the count of client packets, and a count of APP transmit errors, enter:

    (config)# show zone 1 verbose

Table 12-17 describes the fields in the show zone screen.
Table 12-17: Show Zone Display Fields
Field Description

Index

The zone index of the peer. The initial value is 255. Once peer communications are established, the value changes to the zone index of the peer. If peer communications cannot be negotiated, the value remains at 255.

Description

Zone description as supplied by the peer from the dns-server zone command.

IP Address

The IP address of the peer. It corresponds to a locally configured APP session.

State

The state of the proximity peer negotiation, which includes:

  • INIT - Initializing. Waiting for local configuration to complete.

  • SREQ - A connection request message has been sent to the peer.

  • RACK - An acknowledgment message has been received from the peer.

  • SACK - An acknowledgment request has been sent to the peer.

  • OPEN - Negotiations with the peer have completed successfully and the connection is open.

  • CLOSED - Negotiations with the peer have failed and the connection is closed.

State Chgs

The number of times the state has transitioned to OPEN and CLOSED.

UpTime

The amount of time that APP has been in the OPEN state.

Showing DNS-Record Proximity

Use the show dns-record proximity command to display dns-record proximity statistics.

The syntax for this global configuration mode command is:

    # show dns-record proximity

For example:

    (config)# show dns-record proximity

Table 12-18 describes the fields in the show dns-record proximity screen.
Table 12-18: Show DNS-Record Proximity Display Fields
Field Description

<Domain name>

The domain name for the record.

Zone

The index number for the zone. A "*" character preceding the zone number indicates that the zone is a local entry. A value of 255 indi