Table Of Contents
New Software Features in Release 11.3(1)
APPN over Ethernet LAN Emulation
Backup Peer Extensions for Encapsulation Types
Block Serial Tunneling (BSTUN) over Frame Relay
Frame Relay Access Support (FRAS) Boundary Network Node Enhancement
LLC2-to-SDLC Conversion between PU4 Devices
NetBIOS Dial-on-Demand Routing
Source-Route Bridging (SRB) over FDDI on Cisco 4000, 4500, and 4700 Series Routers
Tunneling of Asynchronous Security Protocols
Hot Standby Router Protocol over ISL in Virtual LAN Configurations
IP Enhanced IGRP Route Authentication
AppleTalk Access List Enhancements
Cisco Call History MIB Command Line Interface
Cisco IOS Internationalization
IP Multicast Load Splitting across Equal-Cost Paths
IP Multicast over ATM Point-to-Multipoint Virtual Circuits
IP Multicast over Token Ring LANs
Vendor-Proprietary RADIUS Attributes
AppleTalk Routing over ISL and IEEE 802.10 in Virtual LANs
Banyan VINES Routing over ISL Virtual LANs
CLNS and DECnet Fast Switching Support over PPP
DECnet Routing over ISL Virtual LANs
IPX Routing over ISL Virtual LANs
VIP Distributed Switching Support for IP Encapsulated in ISL
XNS Routing over ISL Virtual LANs
Virtual Interface Template Service
Virtual Templates for Protocol Translation
Bandwidth Allocation Control Protocol
Enhanced Local Management Interface
LANE Per-subinterface Debug Messages
Layer 2 Forwarding—Fast Switching
Multilink PPP Interleaving and Fair-Queuing Support
VPDN Tunnel Lookup Based on Dialed Number Information
X.25 Switching between PVCs and SVCs
New Hardware Support in Release 11.3(1)
Cisco AS2509-RJ and Cisco AS2511-RJ Access Servers
Internet Router Cards for 10BaseT Hubs
16-Port and 32-Port Asynchronous Network Modules for Cisco 3600 Series Routers
Compression Network Module for Cisco 3600 Series Routers
Fast Ethernet for the Cisco 3600 Series Routers
2T16S Network Processor Module (Asynchronous and Synchronous)
2T16S Network Processor Module (Synchronous)
Fast Ethernet Network Interface Module for the Cisco 4000 series
High-Speed Serial Interface Network Processor Module for Cisco 4000 Series Routers
56K 12-Port Modem Modules for the Cisco AS5200 Access Server
Channelized E1 Signaling for the Cisco AS5200
Dual E1 PRI for the Cisco AS5200
Robbed Bit Signaling for the Cisco AS5200
Channelized T3 Interface Processor
Channelized T3 Interface Processor Feature Enhancements
Data Encryption Service Adapter
Clock Rate Command Enhancements
Fast-Switched Fragmented IP Packets on Cisco 7200 Series Routers
Fast-Switched SMRP Packets on Cisco 7200 Series Routers
FDDI Full-Duplex Single-Mode and Multimode Port Adapters
Half-Duplex and Bisync for Synchronous Serial Port Adapters on Cisco 7200 Series Routers
High-Speed Serial Interface Port Adapters
Next-Generation Route Switch Processor (RSP4) on Cisco 7500 Series Routers
PA-2CE1/PRI-75, PA-2CE1/PRI-120, and PA-2CT1/PRI Channelized E1 and T1 Port Adapters
PA-4R-FDX Token Ring Full-Duplex Port Adapter
PA-A1-OC3MM and PA-A1-OC3SM ATM Port Adapters
PA-8B-ST and PA-4B-U Basic Rate Interface Port Adapters
Packet OC-3 Interface Processor
Particle-Based Transparent Bridging on Cisco 7200 Series Routers
RSP Fragmented IP Packets Optimum or Flow Switched
SA-Comp/1 and SA-Comp/4 Data Compression Service Adapters
Selective Packet Discard (SPD)
Synchronous Serial Port Adapters
Turbo Flooding of UDP Datagrams on Cisco 7200 Series Routers
New Features in Release 11.3
Cisco IOS Release 11.3 is a Major Release of software. Maintenance releases of Major Releases deliver fixes to software defects only, thus providing the most stable software for your network, for the features you need.
Note
Cisco IOS Release 11.3 will be a short-lived release, with regularly scheduled maintenance releases planned for at least one year after FCS. Since it is a limited life release, it will not achieve the General Deployment (GD) milestone.
In addition to this Major Release of software, there is an Early Deployment (ED) release based on Release 11.3, called Cisco IOS Release 11.3 T. Release 11.3 T delivers not only fixes to software defects, but also new platform support and new cross-platform functionality.
This release note documents the Major Release only. For information on the ED release, see product-specific release notes on CCO or the Documentation CD-ROM.
This section provides information on the following topics:
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New Software Features in Release 11.3(1)
The following software enhancements have been added to Release 11.3. These features are available in all software trains of Release 11.3. Separate documentation that is available with each release of the ED software trains describes the additional functionality that is available in ED software releases.
This section is divided into the following subjects:
IBM Support
This section describes the IBM network software features that are new in the initial release of Cisco IOS Release 11.3.
APPN High Performance Routing
High Performance Routing (HPR) is an enhancement to APPN that improves network performance and reliability. Considered the next step in the evolution of SNA networking, HPR replaces the APPN routing technique called intermediate session routing (ISR) and provides significant performance improvements over ISR.
HPR replaces ISR with two elements: Rapid Transport Protocol (RTP) and Automatic Network Routing.
RTP is a transport protocol that provides functions including error recovery, packet resequencing, segmentation, selective retransmissions, flow control, and congestion control. It incorporates a new congestion avoidance algorithm, Adaptive Rate-Based congestion control. ARB is preventive rather than a reactive congestion control mechanism and maximizes the usage of limited and costly bandwidth with consistent response time under heavy traffic.
Automatic Network Routing is a new type of connectionless source routing with priority. Automatic Network Routing provides a low level routing mechanism that minimizes cycles and storage requirements for routing packets through intermediate nodes.
Cisco's HPR is compliant with Version 6 of the HPR architecture of record. All functions are interoperable with the following IBM major platforms:
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APPN MIB Enhancements
The router APPN MIB implementation has been updated to support a new MIB definition recently approved by the APPN Implementors Workshop (AIW). The new MIB provides better manageability of APPN network nodes across implementations. It also adds objects for supporting connection networks.
In this release Cisco supports both the current and new MIBs to allow for migration of our application customers from the current version which supports RFC 1593 to a new version for this new MIB.
APPN over Ethernet LAN Emulation
APPN over Ethernet LAN Emulation (LANE) is an enhancement to Cisco's APPN intermediate session routing (ISR) implementation that allows an APPN router to participate in an emulated LAN. APPN over Ethernet LANE enables the APPN network node on the router to communicate with an end system on a switched LAN environment.
APPN Scalability Enhancements
Two new APPN Scalability Enhancement features, Locate Throttling and Negative Caching, allow you to tune your APPN network to conserve network resources by queuing redundant searches and retaining unreachable searches.
The Locate Throttling feature prevents multiple broadcast locate searches that can occur when more than one resource requests sessions with the same destination LU.
The Negative Caching feature prevents excess searches to unreachable resources.
Backup Peer Extensions for Encapsulation Types
Three types of encapsulation are supported in DLSw+: direct, Fast-Sequenced Transport (FST), and TCP. Previously, DLSw+ supported only backup peers for FST and TCP peer types. This new Frame Relay/Direct Backup Peer feature extends the backup peer capability to all types of DLSw+ transportation types.
Bisync 3780 Support
Cisco's Bisync 3780 Support feature has been enhanced to add a user-configurable address on contention interfaces.
BSC Extended Addressing
The Cisco Bisync support protocol stack (BSC) Extended Addressing feature enables the user to configure a set of nonstandard Bisync addresses (for non-IBM Bisync devices that do not use the standard set of 3270 Control Unit addresses).
Block Serial Tunneling (BSTUN) over Frame Relay
The BSTUN over Frame Relay feature provides a tunnel mechanism for Binary Synchronous Communications protocol (bisync) without using TCP/IP encapsulation.
Cisco Multipath Channel
Cisco MultiPath Channel (CMPC) is Cisco Systems' implementation of IBM's MultiPath Channel (MPC) feature. CMPC allows the virtual telecommunications access method (VTAM) to establish Advanced-Peer-to-Peer Networking (APPN) connections using both High Performance Routing (HPR) and Intermediate Session Routing (ISR) through a channel-attached Cisco 7000 series router using the MPC protocols.
DLSw+ Border Peer Caching
With the Border Peer Caching feature, border peers can build three caches (local, remote, and group) and check these caches before forwarding explorers for other routers.
DLSw+ MIB Enhancements
The Cisco DLSw+ Management Information Base (MIB) enhancement feature now includes more information about the "plus" features. For example, the MIB describes the encapsulation type being used: direct, LLC2, FST, and TCP. Furthermore, for FST and direct, which use fast cache entries instead of circuits to establish sessions, the MIB now includes FST and direct cache entries.
The MIB also describes configured defaults for promiscuous and on-demand peers. It provides information about border peers, dynamic peers, and backup peers. Previously the MIB did not know about the remote peer's IP address when using direct or LLC2 encapsulation. Now the remote peer's IP address is sent through the capabilities exchange and listed in the MIB. Finally, the new MIB includes traps for peer up or down and circuit up or down. This MIB provides SNMP network management access to most of the information in the show dlsw capabilities command.
DLSw+ SNA Type of Service
DLSw+ SNA type of service (TOS) sets the IP precedence bits in the IP header of DLSw+ packets. When APPN is running with DLSw+ and the priority option is specified on the dlsw remote peer command, SNA TOS maps APPN class of service (COS) to TCP TOS.
Frame Relay Access Support (FRAS) Boundary Network Node Enhancement
The Frame Relay Access Support (FRAS) Boundary Network Node (BNN) enhancement provides seamless processing at the router regardless of end station changes. End stations can be added or deleted without reconfiguring the router. The FRAS BNN enhancement coexists with the original FRAS BNN feature.
FRAS Dial Backup over DLSw+
Frame Relay Access Support (FRAS) Dial Backup over DLSw+ is an enhancement to Cisco's FRAS implementation that allows you to configure a secondary path that is used when the Frame Relay network becomes unavailable. If preconfigured properly, when the primary link to the Frame Relay WAN fails, FRAS Dial Backup over DLSw+ moves existing sessions to the alternate link automatically. When the primary link is restored, existing sessions are kept on the backup connection so they can be moved nondisruptively to the primary link at the user's discretion.
FRAS DLCI Backup
Frame Relay Access Support (FRAS) DLCI Backup is an enhancement to Cisco's FRAS implementation that lets you configure a secondary serial or ISDN path to the host, to be used when the Frame Relay network becomes unavailable. When the primary Frame Relay link to the Frame Relay WAN fails, the FRAS DLCI Backup feature causes the router to reroute all sessions from the main Frame Relay interface to the secondary interface. The secondary interface can be either serial or ISDN, and must have a data link connection identifier (DLCI) configured.
FRAS Host
The FRAS (Frame Relay Access Support) Host feature provides connectivity from a Systems Network Architecture (SNA) Frame Relay Access Device (FRAD) to a Cisco router for SNA mainframe access. This feature also provides connectivity from remote SNA FRADs to LAN-attached front-end processors (FEPs) or to LAN-attached SNA minicomputers (such as AS/400s).
FRAS MIB
The FRAS Management Information Base (MIB) CISCO-DLCSW-MIB.MY is a collection of managed objects that can be accessed via a network management protocol, such as SNMP. The objects in the MIB support LLC- and SDLC-attached devices for both BNN and BAN formats of RFC 1490. The FRAS MIB user interface is defined by the network manager's SNMP application.
LLC2-to-SDLC Conversion between PU4 Devices
Data-link switching plus (DLSw+) now supports LLC2-to-Synchronous Data Link Control (SDLC) Protocol conversion between PU4 devices. The LLC2-SDLC for PU 4 feature allows a SDLC-attached FEP to communicate over DLSw+ to a LAN-attached FEP.
NetBIOS Dial-on-Demand Routing
DLSw+ now filters NetBIOS Session Alive packets from the WAN. This feature allows you to transport NetBIOS in a dial-on-demand routing (DDR) environment by filtering NetBIOS Session Alive packets. NetBIOS periodically sends Session Alive packets as LLC2 I-frames. These packets do not require a response and are superfluous to the function of proper data flow. Furthermore, these packets keep dial-on-demand interfaces up and this up time causes unwanted per-packet charges in DDR networks.
Source-Route Bridging (SRB) over FDDI on Cisco 4000, 4500, and 4700 Series Routers
This feature extends support for source-route bridging (SRB) on a FDDI interface to the Cisco 4000-M, Cisco 4500-M, and Cisco 4700-M routers. SRB over FDDI is now supported on all Cisco 4000 family routers.
SRB over Frame Relay
Cisco IOS encapsulates source-route bridging (SRB) traffic using RFC 1490 Bridged 802.5 encapsulation to provide SRB over Frame Relay functionality. This functionality may be used between Cisco routers or between a Cisco router and RFC 1490-compliant FRADs or routers.
TN3270 LU Nailing
Logical unit (LU) nailing allows a client IP address to be mapped, or "nailed," to one or more LU local addresses on one or more physical units (PUs) by means of router configuration commands. You can control the relationship between the TN3270 client and the LU.
Clients from traditional TN3270 (non-TN3270E) devices can connect to specific LUs, which overcomes a limitation of TN3270 devices that cannot specify a "CONNECT LU." LU nailing is useful for TN3270E clients because you can perform the configuration at the router, providing central control, rather than at the client.
TN3270 Server Enhancements
The enhancements for the TN3270 server include the following:
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RFC 1646 Printer Support
Cisco provides full RFC 1646 printer support in the TN3270 server. There are no configuration tasks or other options required in the CIP to take advantage of this support. Prior versions of the TN3270 server feature provided RFC 1647 support.
Function Management Header (FMH) Support
The Function Management Header (FMH) support is provided in the context of providing printer support for the Kanji character set. There are no configuration tasks or other options required in the CIP to take advantage of this support.
When a client does not support FMH and the host sends an FMH, the client will report a bad datastream or print random data. Prior to TN3270 server support of FMH, when a host sent an FMH the session would be unbound.
With suitable host and client software, you can now print double-byte character set characters over an LU type 1 session.
Unformatted System Services Table (USSTAB) Conversion
The TN3270 server now translates the host SNA character string (SCS) to 3270DS. In the initial release of TN3270 server, you were required to set up the host to provide either SCS or 3270DS data, depending on the needs of the client. That requirement no longer exists.
IP Type Of Service/Precedence Setting
The TN3270 server supports IP type of service (TOS) precedence setting. TOS is used in router networks to make routing decisions for the generated IP packets. The TN3270 server generates packets that comply to IP TOS/precedence values. (Refer to RFC 1349 for a description of IP TOS/precedence.)
Token Ring LANE
The Token Ring LANE (TR-LANE) feature emulates an IEEE 802.5 Token Ring LAN using ATM technology. LANE provides a service interface for network layer protocols that is identical to existing MAC layers. No changes are required to existing upper layer protocols and applications. With TR-LANE, Token Ring packets are encapsulated in the appropriate ATM cells and sent across the ATM network. When the packets reach the other side of the ATM network, they are de-encapsulated. LANE essentially bridges LAN traffic across ATM switches.
TR-LANE allows legacy Token Ring LAN users to take advantage of ATM's benefits without modifying end-station hardware or software.
ATM uses connection-oriented service with point-to-point signaling or multicast signaling between source and destination devices. However, Token Ring LANs use connectionless service. Messages are broadcasts to all devices on the network. With TR-LANE, routers and switches emulate the connectionless service of a Token Ring LAN for the endstations.
Tunneling of Asynchronous Security Protocols
Cisco's implementation of block serial tunneling (BSTUN) encapsulates Binary Synchronous Communications protocol (Bisync), Adplex, ADT Security Systems, Inc., Diebold, and asynchronous generic traffic for transfer over router links.
Cisco's tunneling of asynchronous security protocols feature (ASP) enables your Cisco 2500, 4000, or 4500 series router to support devices that use the following asynchronous security protocols:
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These protocols enable enterprises to transport polled asynchronous traffic over the same network that supports their Systems Network Architecture (SNA) and multiprotocol traffic, eliminating the need for separate facilities.
UDP Unicast Enhancement
Silicon Switch Processor (SSP) address resolution packets will now be sent via User Datagram Protocol (UDP) unicast service rather than via TCP. SSP packets include: CANUREACH.EX, NETBIOS_NAME_QUERY_EX, NB_ADD_NAME.QUERY_EX, and DATAFRAME.
UDP Unicast enhances the scalability of TCP peer networks because it allows DLSw+ to better control address resolution packets and unnumbered information (UI) frames during periods of congestion. Previously, these frames were carried over TCP. TCP retransmits frames that get lost or delayed in transit, and hence aggravate congestion. Because address resolution packets and UI frames are not sent on a reliable transport on the LAN, sending them reliably over the WAN is unnecessary. By using UDP for these frames, DLSw+ minimizes network congestion.
UDP Unicast Enhancement does not affect Fast-Sequenced Transport (FST) or direct peer encapsulations.
Internet
This section describes the Internet software feature that is new in the initial release of Cisco IOS Release 11.3.
DRP Server Agent
The Director Response Protocol (DRP), a simple User Datagram Protocol (UDP)-based application developed by Cisco Systems, enables Cisco's DistributedDirector product to query routers (DRP Server Agents) in the field for Border Gateway Protocol (BGP) and Interior Gateway Protocol (IGP) routing table metrics between distributed servers and clients. DistributedDirector, a separate standalone product, uses DRP to transparently redirect end-user service requests to the topologically closest responsive server. DRP enables DistributedDirector to provide dynamic, scalable, and "network intelligent" Internet traffic load distribution between multiple geographically dispersed servers.
DRP Server Agents are border routers (or peers to border routers) that support the geographically distributed servers for which DistributedDirector service distribution is desired. Note that, because DistributedDirector makes decisions based on BGP and IGP information, all DRP Server Agents must have access to full BGP and IGP routing tables.
Refer to the Cisco DistributedDirector 2500 Series Installation and Configuration Guide or the Cisco DistributedDirector 4700-M Installation and Configuration Guide for information on how to configure DistributedDirector.
IP Routing
This section describes the IP routing software features that are new in the initial release of Cisco IOS Release 11.3.
Easy IP (Phase 1)
The Easy IP (Phase 1) feature combines Network Address Translation (NAT) and PPP/Internet Protocol Control Protocol (IPCP). This feature enables a Cisco router to automatically negotiate its own registered WAN interface Internet Protocol (IP) address from a central server and to enable all remote hosts to access the global Internet using this single registered IP address. Because Easy IP uses existing port-level multiplexed NAT functionality within the Cisco IOS software, IP addresses on the remote LAN are invisible to the Internet.
Hot Standby Router Protocol over ISL in Virtual LAN Configurations
The Hot Standby Router Protocol (HSRP) provides a very high level of redundancy between hosts and gateway routers. With HSRP, users realize high network availability by enabling backup routes between hosts on Ethernet, Fast Ethernet, FDDI, and Token Ring networks. Cisco IOS devices that are running the HSRP send and receive multicast hello packets to detect router failure and to designate active and standby routers.
HSRP was first introduced with ATM LAN Emulation in Cisco IOS Release 11.0 and in Release 11.1 for virtual LAN (VLAN) configurations in IP networks using IEEE 802.10 encapsulations on FDDI media. Starting with Release 11.3, HSRP is also supported over Inter-Switch Links (ISLs) in VLAN configurations on FastEthernet. Now, HSRP functionality can be deployed with Cisco IOS VLANS using IEEE 802.10 on FDDI, ATM LAN Emulation, and ISL encapsulation on Fast Ethernet.
IP Enhanced IGRP Route Authentication
This feature provides MD5 authentication of routing updates from the IP EIGRP routing protocol. The MD5 keyed digest in each IP Enhanced IGRP packet prevents the introduction of unauthorized or false routing messages from unapproved sources.
TCP Selective Acknowledgment
The TCP selective acknowledgment feature improves performance in the event that multiple packets are lost from one TCP window of data.
Prior to this feature, with the limited information available from cumulative acknowledgments, a TCP sender could learn about only one lost packet per round-trip time. An aggressive sender could choose to retransmit packets early, but such retransmitted segments might have already been successfully received.
The TCP selective acknowledgment mechanism helps improve performance. The receiving TCP host returns selective acknowledgment packets to the sender, informing the sender of data that has been received. In other words, the receiver can acknowledge packets received out of order. The sender can then retransmit only the missing data segments (instead of everything since the first missing packet).
Prior to selective acknowledgment, if TCP lost packets 4 and 7 out of an 8-packet window, TCP would receive acknowledgment of only packets 1, 2, and 3. Packets 4 through 8 would have to be resent. With selective acknowledgment, TCP receives acknowledgment of packets 1, 2, 3, 5, 6, and 8. Only packets 4 and 7 have to be resent.
Refer to RFC 2018 for more detailed information on TCP selective acknowledgment.
TCP Timestamp
The TCP timestamp option provides better TCP round-trip time measurements. Because the timestamps are always sent and echoed in both directions and the timestamp value in the header is always changing, TCP header compression will not compress the outgoing packet. To allow TCP header compression over a serial link, the TCP timestamp option is disabled.
Refer to RFC 1323 for more detailed information on TCP timestamp.
LAN Support
This section describes the LAN support software features that are new in the initial release of Cisco IOS Release 11.3.
AppleTalk Access List Enhancements
This feature adds functionality and improved performance when using AppleTalk access lists and filters.
The specific AppleTalk access list enhancements include the following:
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In previous releases of the Cisco IOS software, AppleTalk access lists, with the exception of NBP access lists, could be applied to outbound interfaces only. With this release, access lists can be applied to inbound and outbound interfaces.
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In previous releases of Cisco IOS software, NBP access lists could be applied to inbound interfaces only. With this release, NBP access lists can be applied to inbound and outbound interfaces.
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DECnet Accounting
DECnet Accounting allows you to collect information about DECnet packets and the number of bytes that are switched through the Cisco IOS software. You collect accounting information based on the source and destination DECnet addresses. DECnet accounting tracks only DECnet traffic that is routed out an interface on which DECnet accounting is configured; it does not include traffic generated by or terminating at the router itself.
IPX Named Access Lists
This feature allows you to identify IPX access lists with an alphanumeric string (a name) rather than a number. This feature allows you to configure an unlimited number of the following types of access lists:
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If you identify your access list with a name rather than a number, the mode and command syntax are slightly different. Currently, only packet and route filters can use a named list.
This feature allows you to maintain security by using a separate and easily identifiable access list for each user or interface. It also removes the limit of 100 lists per filter type.
Consider the following before configuring IPX named access lists:
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IPX SAP-after-RIP
This feature links Service Advertising Protocol (SAP) updates to Routing Information Protocol (RIP) updates so that SAP broadcast and unicast updates automatically occur immediately after the completion of the corresponding RIP update. It ensures that no service information will be rejected by a remote router because it lacks a valid route to the service. As a result of this feature, periodic SAP updates are sent at the same frequency as RIP updates.
The default behavior of the router is to send RIP and SAP periodic updates with each using its own update interval, depending on the configuration. In addition, RIP and SAP periodic updates are jittered slightly, such that they tend to diverge from each other over time. This feature synchronizes SAP and RIP updates.
In addition, it is now possible to disable the sending of general RIP and/or SAP queries on a link when it first comes up.
Sending all SAP and RIP information in a single update reduces bandwidth demands and eliminates erroneous rejections of SAP broadcasts.
Linking SAP and RIP updates populates the service table at the remote router more quickly, because services will not be rejected due to the lack of a route to the service. This can be especially useful on WAN circuits where the update intervals have been greatly increased to reduce the overall level of periodic update traffic on the link.
RIP and SAP general queries are normally sent by remote routers when a circuit first comes up. On WAN circuits, two full updates of each kind are often sent across the link. The first update is a full broadcast update, triggered locally by the link-up event. The second update is a specific (unicast) reply triggered by the general query received from the remote router. By disabling the sending of general queries when the link first comes up, it is possible to reduce traffic to a single update, and save bandwidth.
NLSP Enhancements
This feature allows the router to interpret the maximum lifetime field in a Level 1 link-state packet (LSP) in hours or seconds. Previously, the field was interpreted in seconds only.
By being able to interpret the maximum lifetime field in hours, the router will be able to keep LSP packets for a much longer time which will reduce overhead on slower-speed serial links and keep ISDN links from becoming active unnecessarily.
NLSP Multicast Support
The NLSP Multicast Support feature adds support for the use of NLSP multicast addressing for Ethernet, Token Ring, and FDDI router interfaces. This capability is only possible when the underlying Cisco hardware device or driver supports multicast addressing.
With this feature, the router defaults to using multicasts on Ethernet, Token Ring, and FDDI interfaces, instead of broadcasts, to address all NLSP routers on the network. If an adjacent neighbor does not support NLSP multicasting, the router will revert to using broadcasts on the affected interface.
When routers running prior versions of Cisco IOS software are present on the same network with routers running Cisco IOS Release 11.3 software, broadcasts will be used on any segment shared by the two routers.
Management
This section describes the Management software features that are new in the initial release of Cisco IOS Release 11.3.
Cisco Call History MIB Command Line Interface
A Cisco IOS command line interface is available for setting two Cisco Call History MIB parameters. These parameters are the number of entries to be retained by the MIB and the length of time to retain them, which correspond to the following MIB objects:
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When you save the router configuration before reloading the router, the parameter values are also saved.
Before this release, SNMP was the only available means for setting the values of these parameters. However, when the parameters are set by SNMP, the old values are lost and the parameters are reset to their default values whenever a router is reloaded.
The Cisco Call History MIB command line interface is enabled by default.
Cisco IOS Internationalization
The Cisco IOS Internationalization feature allows you to use HTML Server Side Includes (SSIs) to customize international or non-international HTML pages used for the Cisco Web browser interface (for example, ClickStart pages) and store them in Flash memory on multiple Cisco IOS platforms. In addition, this feature allows you to display 8-bit or multibyte international character sets (for example, Japanese) and print the escape (ESC) character as a single character instead of as the caret and bracket symbols (^[) on the Cisco Web browser and at the router command line.
Entity MIB, Phase 1
The Entity MIB (RFC 2037) describes the logical resources, physical resources, and logical-to-physical mappings of devices managed by a single SNMP agent. This feature implements the first phase of the Entity MIB, the Logical Entity Table. The Logical Entity Table describes the logical entities managed by a single agent. The Entity MIB also records the time of the last modification to any object in the Entity MIB and sends out a trap when any object is modified. The Entity MIB provides no managed objects with write access.
SNMPv2C
The SNMPv2C feature replaces support for SNMPv2Classic with support for SNMPv2 and SNMPv2C. SNMPv2C replaces the Party-based Administrative and Security Framework of SNMPv2Classic with the Community-based Administrative Framework while retaining 64-bit counters and get-bulk functionality. This feature implements RFCs 1901 through 1907, deprecating the implementation of RFCs 1441 through 1451.
Cisco IOS software continues to support SNMPv1.
The following commands are obsolete in Release 11.3:
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In addition, the snmp-server trap-authentication command has been deprecated. Use the snmp-server enable traps snmp authentication command in its place. Existing configurations that use the snmp-server trap-authentication command are not affected; however, this command will not be saved to the startup configuration.
Virtual Profiles
Virtual profiles is a unique PPP application that defines and applies per-user configuration information for users who dial in to a router. Virtual profiles allow user-specific configuration information to be applied irrespective of the media used for the dial-in call. The configuration information for virtual profiles can come from a virtual interface template, per-user configuration information stored on an AAA server, or both, depending on how the router and AAA server are configured.
Virtual profiles are intended to overcome current limitations on network scalability:
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Virtual profiles overcome the limitations listed above by providing a unique interface for each user dialing in to a Cisco router/access server.
Multimedia
This section describes the multimedia software features that are new in the initial release of Cisco IOS Release 11.3.
IP Multicast Load Splitting across Equal-Cost Paths
You can now configure load splitting of IP multicast traffic across equal-cost paths. Prior to this feature, when there were equal-cost paths between routers, IP multicast packets traversed only one path. If a tunnel was configured, the same next hop was always used, and no load splitting occurred.
IP multicast load splitting is accomplished indirectly by consolidating the available bandwidth of all the physical links into a single tunnel interface. The underlying physical connections then use existing unicast load-splitting mechanisms for the tunnel (multicast) traffic.
Note: This feature is load splitting the traffic, not load balancing the traffic.
By configuring load splitting among equal-cost paths, you can use your links between routers more efficiently when sending IP multicast traffic.
IP Multicast over ATM Point-to-Multipoint Virtual Circuits
IP multicast over ATM point-to-multipoint virtual circuits is a feature that dynamically creates ATM point-to-multipoint switched virtual circuits (SVCs) to handle IP multicast traffic more efficiently. The feature can enhance router performance and link utilization because packets are not replicated and sent multiple times over the ATM interface.
IP Multicast over Token Ring LANs
Prior to this feature, IP multicast datagrams used the MAC-level broadcast address 0xFFFF.FFFF.FFFF. That placed an unnecessary burden on all devices that did not participate in IP multicast. The IP multicast over Token Ring LANs feature defines a way to map IP multicast addresses to a single Token Ring MAC address. This feature defines the Token Ring functional address (0xc000.0004.0000) that should be used over Token Ring.
Cisco Systems' implementation complies with RFC 1469, IP Multicast over Token-Ring Local Area Networks (June 1993).
IP multicast transmissions over Token Ring interfaces are more efficient than they used to be. This feature reduces the load on other machines that do not participate in IP multicast because they do not receive these packets.
The following restrictions apply to this feature:
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Stub IP Multicast Routing
When using PIM in a large network, there are often stub regions over which the administrator has limited control. To reduce the configuration and administration burden, you can configure a subset of PIM functionality that provides the stub region with connectivity, but does not allow it to participate in or potentially complicate any routing decisions.
Stub IP multicast routing allows simple multicast connectivity and configuration at stub networks. It eliminates periodic flood-and-prune behavior across slow-speed links (ISDN and below) using dense mode. It does this by using forwarded IGMP reports as a type of Join message and selective PIM message filtering.
Quality of Service
This section describes the quality of service software features that are new in the initial release of Cisco IOS Release 11.3.
RTP Header Compression
Real-time Transport Protocol (RTP) is a protocol used for carrying packetized audio and video traffic over an IP network. RTP is described in RFC 1889. RTP is not intended for data traffic, which uses Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). RTP provides end-to-end network transport functions intended for applications transmitting real-time requirements, such as audio, video, or simulation data over multicast or unicast network services.
The minimal 12 bytes of the RTP header, combined with 20 bytes of IP header and 8 bytes of UDP header create a 40-byte IP/UDP/RTP header. The RTP packet has a payload of approximately 20 to 150 bytes for audio applications that use compressed payloads. It is very inefficient to transmit the IP/UDP/RTP header without compressing it.
The RTP header compression feature compresses the IP/UDP/RTP header in an RTP data packet from 40 bytes to approximately 2 to 5 bytes. It is a hop-by-hop compression scheme similar to RFC 1144 for TCP header compression. Using RTP header compression can benefit both telephony voice and multicast backbone (MBONE) applications running over slow links.
RTP header compression is supported on serial lines using Frame Relay, HDLC, or PPP encapsulation. It is also supported over ISDN interfaces.
Enabling compression on both ends of a low-bandwidth serial link can greatly reduce the network overhead if there is a lot of RTP traffic on that slow link. This compression is beneficial especially when the RTP payload size is small (for example, compressed audio payloads of 20-50 bytes). Although the MBONE-style RTP traffic has higher payload sizes, compact encodings like Compressed Encoding for Linear Prediction (CELP) can also help considerably.
Security
This section describes the security software features that are new in the initial release of Cisco IOS Release 11.3.
Double Authentication
Double Authentication provides additional authentication for Point-to-Point Protocol (PPP) sessions. Previously, PPP session authentication was limited to CHAP (or PAP). With Double Authentication, you essentially require remote users to pass a second stage of user authentication—after CHAP or PAP authentication—before they can gain network access.
If you configure your local host (NAS or router) for Double Authentication, remote users will be required to complete a second stage of authentication to gain their assigned user network privileges. This second ("double") authentication requires a password that is known to the user but not stored on the user's remote host. Therefore, the second authentication is specific to a user, not to a host. This feature provides an additional level of security that is effective even if the remote host is stolen.
Encrypted Kerberized Telnet
Encrypted Kerberized Telnet enables a router to initiate or receive an encrypted Telnet session. Previously, all Telnet session traffic could only be transmitted as cleartext (readable) data.
You can use Encrypted Kerberized Telnet when establishing a Telnet session to or from a router. When you use this feature, first you are authenticated by your Kerberos credentials, and then an encrypted Telnet session is established.
Cisco's Encrypted Kerberized Telnet uses the following encryption standard: 56-bit Data Encryption Standard (DES) encryption with 64-bit Cipher Feedback (CFB).
This feature is available only if you have the 56-bit encryption image. 56-bit DES encryption is subject to U.S. government export control regulations.
HTTP Security
All Cisco routers and access servers running Cisco IOS Release 11.0(6) or later have an HTTP server, which is an embedded subcomponent of the Cisco IOS software. The HTTP server allows users with a privilege level of 15 to issue Cisco IOS commands from a predefined home page using a Web browser. Cisco IOS software currently allows only users with a privilege level of 15 to access the Cisco Web browser interface. In Cisco IOS Release 11.3, the HTTP security feature enables users with a privilege level other than 15 to access the HTTP server.
In addition, a new command has been added to specify how HTTP server users are authenticated. The HTTP server in the Cisco IOS Release 11.2 software uses the enable password method to authenticate a user at privilege level 15. In Release 11.3, system administrators can now specify enable; local; Terminal Access Controller Access Control System (TACACS); or authentication, authorization, and accounting (AAA) user authentication.
The HTTP Security feature enables network administrators to provide HTTP server access to users with a privilege level of less than 15. This feature allows the Cisco Web browser interface to mirror the functionality of the command-line interface (CLI).
Per-User Configuration
The per-user configuration can tie together the following dial-in features:
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A virtual access interface created dynamically for any user dial-in session is deleted when the session ends. The resources used during the session are returned for other dial-in uses.
With per-user configuration:
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Reflexive Access Lists
Reflexive access lists allow IP packets to be filtered based on upper-layer session information. You can use reflexive access lists to permit IP traffic for sessions originating from within your network, but to deny IP traffic for sessions originating from outside your network. This is known as "reflexive" filtering, a type of session filtering.
Reflexive access lists can be defined with extended named IP access lists only. You cannot define reflexive access lists with numbered or standard named IP access lists, or with other protocol access lists.
TCP Intercept
The TCP intercept feature implements software to protect TCP servers from TCP SYN-flooding attacks, which are a type of denial-of-service attack.
A SYN-flooding attack occurs when a hacker floods a server with a barrage of requests for connection. Because these messages have unreachable return addresses, the connections cannot be established. The resulting volume of unresolved open connections eventually overwhelms the server and can cause it to deny service to valid requests, thereby preventing legitimate users from connecting to a Web site, accessing e-mail, using FTP service, and so on.
The TCP intercept feature helps prevent SYN-flooding attacks by intercepting and validating TCP connection requests. In intercept mode, the TCP intercept software intercepts TCP synchronization (SYN) packets from clients to servers that match an extended access list. The software establishes a connection with the client on behalf of the destination server and, if successful, establishes the connection with the server on behalf of the client and knits the two half-connections together transparently. Thus, connection attempts from unreachable hosts will never reach the server. The software continues to intercept and forward packets throughout the duration of the connection.
Vendor-Proprietary RADIUS Attributes
Remote Authentication Dial-In User Server (RADIUS) is an access server authentication and accounting protocol originally developed by Livingston, Inc. Although an Internet Engineering Task Force (IETF) draft standard for RADIUS specifies a method for communicating vendor-proprietary information between the network access server and the RADIUS server, some vendors have extended the RADIUS attribute set in a unique way. Cisco IOS software currently supports the IETF draft standard RADIUS. In this release, Cisco IOS software introduces support for the most common vendor-proprietary RADIUS attributes.
Some vendor-proprietary implementations of RADIUS let the administrator define static routes and IP pool definitions on the RADIUS server, instead of on each individual network access server. As each network access server starts up, it queries the RADIUS server for static route and IP pool information. In this release, a new command enables the Cisco router to obtain static routes and IP pool definition information from the RADIUS server at start-up time. This frees the user from having to configure such information on each individual network access server.
Switching
This section describes the switching software features that are new in the initial release of Cisco IOS Release 11.3.
AppleTalk Routing over ISL and IEEE 802.10 in Virtual LANs
AppleTalk can now be routed over virtual LAN (VLAN) subinterfaces using ISL and IEEE 802.10 VLAN encapsulating protocols.
The AppleTalk Routing over ISL and IEEE 802.10 in Virtual LANs feature provides full-feature Cisco IOS AppleTalk support on a per-VLAN basis, allowing standard AppleTalk capabilities to be configured on VLANs. This feature allows users to configure consolidated VLAN routing over a single VLAN trunking interface. Prior to introduction of this feature, AppleTalk could be routed only on the main interface on a LAN port. If AppleTalk routing was disabled on the main interface or if the main interface was shut down, the entire physical interface would stop routing any AppleTalk packets. With this feature enabled, AppleTalk routing on subinterfaces will be unaffected by changes in the main interface.
Banyan VINES Routing over ISL Virtual LANs
Banyan VINES can now be routed over virtual LAN (VLAN) subinterfaces using the ISL encapsulation protocol. The Banyan VINES Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software Banyan VINES support on a per-VLAN basis, allowing standard Banyan VINES capabilities to be configured on VLANs.
CLNS and DECnet Fast Switching Support over PPP
Cisco now supports fast switching of incoming and outgoing DECnet and CLNS packets over PPP.
DECnet Routing over ISL Virtual LANs
DECnet can now be routed over virtual LAN (VLAN) subinterfaces using the ISL VLAN encapsulation protocols. The DECnet Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software DECnet support on a per-VLAN basis, allowing standard DECnet capabilities to be configured on VLANs.
Fast-Switched Policy Routing
IP policy routing can now be fast-switched. Prior to this feature, policy routing could only be process switched, which meant that on most platforms, the switching rate was approximately 1,000 to 10,000 packets per second. This was not fast enough for many applications. Users who need policy routing to occur at faster speeds can now implement policy routing without slowing down the router.
IPX Routing over ISL Virtual LANs
The IPX Routing over ISL Virtual LANs (VLANs) feature extends Novell NetWare routing capabilities to include support for routing all standard IPX encapsulations for Ethernet frame types in VLAN configurations. Users with Novell NetWare environments can now configure any one of the four IPX Ethernet encapsulations to be routed using the Inter-Switch Link (ISL) encapsulation across VLAN boundaries. IPX encapsulation options now supported for VLAN traffic include:
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VIP Distributed Switching Support for IP Encapsulated in ISL
With this feature, Inter-Switch Link (ISL) encapsulated IP packets can be switched on Versatile Interface Processor (VIP) controllers installed on Cisco 7500 series routers.
VIP distributed switching offloads switching of ISL VLAN IP traffic to the VIP card, removing involvement from the main CPU. Offloading ISL traffic to the VIP card, significantly improves networking performance. Because you can install multiple VIP cards in a router, VLAN routing capacity is increased linearly according to the number of installed VIP cards.
XNS Routing over ISL Virtual LANs
XNS can now be routed over virtual LAN (VLAN) subinterfaces using the ISL VLAN encapsulation protocol. The XNS Routing over ISL Virtual LANs feature provides full-feature Cisco IOS software XNS support on a per-VLAN basis, allowing standard XNS capabilities to be configured on VLANs.
Terminal Services
This section describes the terminal services software features that are new in the initial release of Cisco IOS Release 11.3.
Virtual Interface Template Service
Beginning with Cisco IOS Release 11.2, virtual interfaces can be configured independently of any physical interface and applied dynamically, as needed, to create virtual access interfaces. When a user dials in, a predefined configuration template is used to configure a virtual access interface; when the user is done, the virtual access interface is torn down and the resources are freed for other dial-in uses.
This feature provides a generic service that can be used to apply predefined configurations (virtual interface templates) in creating and freeing virtual access interfaces on the fly, as needed.
Virtual interface templates and virtual access interfaces are basically serial interfaces with no hardware associations; they are created and freed as needed.
The virtual interface template service provides the following benefits to customers with large numbers of dial-in users:
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Virtual Templates for Protocol Translation
Cisco IOS software Release 11.3 enables you to simplify the process of configuring protocol translation to tunnel PPP or SLIP across X.25, TCP, and LAT networks. It does so by providing virtual template interfaces that you can configure independently and apply to any protocol translation configuration. You can configure virtual interface templates for one-step and two-step protocol translation.
Before virtual templates were implemented, you enabled asynchronous protocol functions on VTY lines by creating virtual asynchronous interfaces rather than virtual access interfaces. (For one-step translation, you did so by specifying ppp or slip as outgoing options in the translate command. For two-step translation, you did so by specifying the vty-async command.) The differences between virtual asynchronous interfaces and virtual access interfaces are as follows:
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Virtual access interfaces replace virtual asynchronous interfaces for both one-step and two-step translation.
WAN Optimization
This section describes the WAN optimization software features that are new in the initial release of Cisco IOS Release 11.3.
ATM MIB Enhancements
The Cisco AAL5 MIB adds a proprietary extension to the standard ATM MIB (RFC 1695) to provide per-VC statistic counters that are currently displayed in response to the Cisco IOS show atm vc vcd command for ATM interfaces. This MIB extension allows SNMP network management system applications to query the same variables (SNMP objects) as those that can be gathered from the Cisco IOS command line interface.
PAD Enhancements
Cisco's implementation of packet assembler/disassembler (PAD) has been enhanced:
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PAD Subaddressing
This feature allows you to append a specified value to an X.121 calling address, if the X.121 calling address is not sufficient to identify the source of a call. PAD subaddressing allows you to create unique X.121 calling addresses by including either a physical port number or a value specified for a line as a subaddress to the X.121 calling address.
PAD subaddressing enables an X.25 host application to uniquely identify the source of an X.121 call. For example, in some bank security alarm applications, the central alarm host identifies the physical location of the alarm units from subaddressing information contained in the Call Request packet.
WAN Services
This section describes the WAN services software features that are new in the initial release of Cisco IOS Release 11.3.
Bandwidth Allocation Control Protocol
The Bandwidth Allocation Control Protocol (BACP), described in RFC 2125, provides Multilink PPP peers with the ability to govern link utilization. Once peers have successfully negotiated BACP, they can use the Bandwidth Allocation Protocol (BAP), which is a subset of BACP, to negotiate bandwidth allocation. BAP provides a set of rules governing dynamic bandwidth allocation through call control; a defined method for adding and removing links from a multilink bundle for Multilink PPP is used.
The addition of any link to an existing multilink bundle is controlled by a BAP call or callback request message, and the removal of a link can be controlled by a link drop message.
BACP is designed to operate in both the virtual interface environment and the dialer interface environment. It can operate over any physical interface that is PPP multilink capable and has a dial capability; at initial release, BACP supports ISDN and asynchronous serial interfaces.
BACP provides the following benefits:
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Enhanced Local Management Interface
The Enhanced Local Management Interface feature provides an enhancement to the Frame Relay LMI protocol. Enhanced Local Management Interface enables automated exchange of Frame Relay QoS parameter information between the Cisco router and the Cisco StrataCom switch. Routers can base congestion management and prioritization decisions on known QoS values, such as the Committed Information Rate (CIR), Committed Burst Size (Bc), and Excess Burst Size (Be). The router senses Quality of Service (QoS) values from the switch and can be configured to use those values in traffic shaping. This enhancement works between Cisco routers and Cisco StrataCom switches (BPX/AXIS and IGX platforms).
Frame Relay Enhancements
The Frame Relay Enhancements introduced with this feature include:
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Frame Relay compression can now occur on the VIP board, on the CSA, or on the main CPU of the router. FRF.9 is standard-based and therefore provides multivendor compatibility. FRF.9 compression uses higher compression ratios, allowing more data to be compressed for faster transmission.
The CSA hardware has been in use on the Cisco 7200 series and Cisco 7500 series platforms, but it has had no support for Frame Relay compression. FRF.9 compression provides the ability to maintain multiple decompression/compression histories on a per-DLCI basis.
Frame Relay MIB Extensions
The Cisco Frame Relay MIB adds proprietary extensions to the standard Frame Relay MIB (RFC 1315). It provides additional link-level and virtual circuit-level information and statistics that are mostly specific to Cisco Frame Relay implementation. This MIB provides SNMP network management access to most of the information covered by the show frame-relay commands, such as, show frame-relay lmi, show frame-relay pvc, show frame-relay map, and show frame-relay svc.
Frame Relay Router ForeSight
ForeSight is the network traffic control software used in Cisco StrataCom switches. The Cisco StrataCom Frame Relay switch can extend ForeSight messages over a User-to-Network Interface (UNI), passing the backward congestion notification for virtual circuits.
The Router ForeSight feature allows Cisco Frame Relay routers to process and react to ForeSight messages and adjust virtual circuit level traffic shaping in a timely manner.
The Router Foresight feature must be configured explicitly on both the Cisco router and the Cisco StrataCom switch. When ForeSight is enabled, a ForeSight message is sent out periodically based the configured time interval, which can range form 40 to 5000 milliseconds. The time interval between the ForeSight messages is set during configuration of the StrataCom switch. Refer to the appropriate StrataCom documentation for details of configuring this feature.
When a Cisco router receives a ForeSight message indicating that certain Data Link Connection Identifiers (DLCIs) are experiencing congestion, the Cisco router reacts by activating its traffic shaping function to slow down the output rate. The router reacts as it would if it were to detect the congestion by receiving a packet with the backward explicit congestion notification (BECN) bit set.
The difference between the BECN and ForeSight methods is that BECN requires a user packet to be sent in the direction of the congested DLCI to convey the signal. The sending of user packets is not predictable and, therefore, not reliable as a notification mechanism. Rather than waiting for user packets to provide the congestion notification, timed ForeSight messages guarantee that the router receives notification before congestion becomes a problem. Traffic can be slowed down in the direction of the congested DLCI.
The Frame Relay Router ForeSight feature provides an improved mechanism for managing network traffic. It provides these benefits:
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ISDN Advice of Charge
The ISDN Advice of Charge (AOC) feature is for ISDN PRI NET5 and ISDN BRI NET3 switch types only. This feature allows users to obtain charging information for all calls during the call (AOC-D) or at the end of the call (AOC-E) or both. Users must have subscribed through their local ISDN network for the ISDN services (AOC-D or AOC-E). No router configuration changes are required to retrieve this call charging information.
The ISDN AOC feature also supports, for the AOC-D service, an optional configurable short-hold mode which provides a dynamic idle timeout by measuring the call charging period, based on the frequency of the AOC-D or the AOC-E message from the network. The short-hold mode idle time will do the following:
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Call accounting information for AOC-D and AOC-E messages is stored in SNMP MIB objects.
This feature can allow users to track call costs and to control and possibly reduce tariff charges through the use of the short-hold mode option.
ISDN Caller ID Callback
The ISDN caller ID callback feature allows the initial incoming call from the client to the server to be rejected based on the caller ID message contained in the ISDN setup message, and allows a callback to be initiated to the calling destination.
In Cisco IOS Release 11.2, ISDN callback functionality required PPP or Combinet Packet Protocol (CPP) client authentication and client-server callback negotiation to proceed. If authentication and callback negotiation were successful, the callback server had to disconnect the call and then place a return call. Both the initial call and the return call were subject to tolls, and when service providers charge by the minute, even brief calls could be expensive.
This feature is independent of the encapsulation in effect and can be used with various encapsulations, such as PPP, HDLC, Frame Relay, and X.25.
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ISDN NFAS
ISDN Non-Facility Associated Signaling (NFAS) allows a single D channel to control multiple PRI interfaces. A backup D channel can also be configured for use when the primary NFAS D channel fails.
Use of a single D channel to control multiple PRI interfaces can free B channel on each interface to carry other traffic.
Once the controllers are configured, only the NFAS primary D channel must be configured; its configuration is distributed to all the members of the associated NFAS group.
LANE Per-subinterface Debug Messages
This feature allows you to limit debug messages to those related to a particular subinterface. Some debug commands generate a large amount of output; by restricting output to information on a particular subinterface, you can reduce the number of debug messages generated.
Layer 2 Forwarding—Fast Switching
Cisco routers now fast switch Layer 2 Forwarding (L2F) traffic. In stack group environments in which some L2F traffic is offloaded to a powerful router, fast switching provides improved scalability.
Leased Line ISDN at 128 kbps
In Cisco IOS Release 11.2, leased-line service at 64 kbps via ISDN BRI is provided in Japan and Germany. In Cisco IOS Release 11.3, leased line service at 128 kbps via ISDN BRI is provided in Japan. This service combines two B channels into a single pipe.
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Multilink PPP Interleaving and Fair-Queuing Support
Interleaving on Multilink PPP allows large packets to be multilink encapsulated and fragmented into a small enough size to satisfy the delay requirements of real-time traffic; small real-time packets are not multilink encapsulated and are transmitted between fragments of the large packets. The interleaving feature also provides a special transmit queue for the smaller, delay-sensitive packets, enabling them to be transmitted earlier than other flows.
Weighted fair-queuing on Multilink PPP works on the packet level, not at the level of multilink fragments. Thus, if a small real-time packet gets queued behind a larger best-effort packet and no special queue has been reserved for real-time packets, the small packet will be scheduled for transmission only after all the fragments of the larger packet are scheduled for transmission.
Weighted fair-queuing is now supported on all interfaces that support Multilink PPP, including Multilink PPP virtual access interfaces and virtual interface templates. Weighted fair-queuing is enabled by default.
Fair-queuing on Multilink PPP overcomes a prior restriction. Previously, fair-queuing was not allowed on virtual access interfaces and virtual interface templates. Interleaving provides the delay bounds for delay-sensitive voice packets on a slow link that is used for other best-effort traffic.
PPP over ATM
This feature enables a high-capacity central site router with an Asynchronous Transfer Mode (ATM) interface to terminate multiple Point-to-Point Protocol (PPP) connections. These PPP connections are typically received from remote branch offices that have PPP-compatible devices interconnecting directly to StrataCom ATM Switch Interface Shelf (AXIS) equipment through a leased-line connection.
A logical interface known as a virtual access interface associates each PPP connection to an ATM permanent virtual circuit (PVC). This configuration allows the PPP protocol to terminate at the router ATM interface as if received from a typical PPP serial interface. Each PPP connection is encapsulated in a separate ATM PVC, which acts as the physical medium over which PPP frames are transported.
The virtual access interface for each PVC obtains its configuration from a virtual template when the PVC is created. All PPP parameters are managed within the virtual template configuration. Multiple virtual access interfaces can spawn from a single virtual template, hence multiple PVCs can use a single virtual template.
The virtual access interface remains associated with a PVC as long as the PVC is configured. Once the PVC is deconfigured, the virtual access interface is marked as deleted. Shutting down the associated ATM interface also causes the virtual access interface to be marked as down (within 10 seconds), bringing the PPP connection down. If a keepalive timer of the virtual template is set on the interface, the virtual access interface uses the PPP echo mechanism to verify the existence of the remote peer. If an interface failure is detected and the PPP connection is brought down, the virtual access interface remains up.
This feature is ideally suited for enterprise customers or customers who use Cisco StrataCom ATM switches to access wide-area networks (WANs) or public ATM networks, such as organizations with many remote branch offices requiring access to high-density corporate headquarters.
Telnet Extensions for Dialout
The Telnet Extensions for Dialout feature is the network access server component of the Cisco DialOut Utility, which enables local users to send faxes or connect to services outside the LAN by using modems attached (or internal) to a network access server. This feature extends the functionality of Telnet by enabling users to control the activity of these modems from their desktop computers using standard communications software. Because the Telnet Extensions for Dialout feature works in conjunction with the client/desktop Cisco DialOut Utility, it is not a standalone feature. It enables the network access server to interface with the client/desktop component of the Cisco DialOut Utility. The client/desktop component of Cisco DialOut Utility must be installed on the client workstation before this feature can be used.
Telnet extensions allow the communications software running on the client's desktop computer to control modem settings, such as baud rate, parity, bit size, and stop bits. In addition, these extensions allow the network access server to return Carrier Detect signals to the communications software so that the software can determine when to start dialing a particular number.
The Telnet Extensions for Dialout feature uses reverse Telnet to access modems attached to the network access server. To enable this feature, you only need to configure the access server or router for reverse Telnet and configure the appropriate lines to both send and receive calls.
VPDN Tunnel Lookup Based on Dialed Number Information
The network service provider can select a specific VPDN tunnel for outgoing calls from a dial-in user by using the Dialed Number Information Service (DNIS) information provided on ISDN lines.
The ability to select a tunnel based on DNIS provides additional flexibility to network service providers who offer VPDN services and to the corporations that use the services. Instead of having to use only the domain name for tunnel selection, tunnel selection can be based on the dialed number.
With this feature, a corporation—which might have only one domain name—can provide multiple specific phone numbers for users to dial in to the network access server at the service provider's point of presence. The service provider can select the tunnel to the appropriate services or portion of the corporate network based on the dialed number.
X.25 Enhancements
Cisco's X.25 offerings have been restructured to meet additional design goals that include greater modularity and consistent availability of X.25 services to the code that uses them. The following have been updated:
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