The type of link management used has no bearing on the format of the Q.922 UI frame.

Trace Example

The following is an example of a frame relay port trace of Modulo 8 X.25 logical port link activation (X.25 encapsulated in frame relay per RFC1490):

0016

(0008)

030851816780013F

(LAPB SABM)

0016

(0008)

0308518167800173

(LAPB UA)

0016

(0013)

03085181678003001000FB0700(LAPB Information frame

0016

(0013)

03085181678001201000FB8700(LAPB Information frame)

0016

(0008)

0308518167800121

(LAPB Receiver Ready)

0016

(0008)

0308518167800331

(LAPB Receiver Ready)

0016

(0008)

0308518167800331

(LAPB Receiver Ready)

In RFC1490 encapsulation, theLAPBb frame follows the T1.618 header, Q.922 control byte, Q.933 NLPID and the level 2 and 3 protocol IDs (2 bytes each). SNA, APPN, X.25, IP, IPX traffic are identified on the DLCI based on their NLPIDs, as well as (if applicable) level 2 and 3 headers (e.g., X.25: 0x03 Q.922 control, 0x08 Q.933 NLPID, T1.617 L2 LAPB PID 0x51 81, T1.617 L3 PID 0x67 80, LAPB frame. For instance, 013F is a LAPB SABM frame.)

Frame Format Examples (in hex)

 

 

 

 

 

IP/IPX over RFC1490:

 

 

 

 

 

Flag AddressCtrl

PAD NLPID OUI PID

Data

FCS Flag

Routed IP

03

CC

 

(start of IP header 45..)

Routed IPX

03

00 80

000000 8137

 

 

X.25 over RFC1490:

Ctrl

NLPID Lvl2PID

Lvl3PID

Data

FCS Flag

03

08

5181

6780

LAPB frame, X.25 packet

Native LLC2 Protocols (Native LLC2 over frame relay is also called BNN):

SNA FID4

Ctrl

NLPID Lvl2PID Lvl3PID LLC2 Data FCS Flag

03

08

4C80

7081

SNA FID2

03

08

4C80

7082

SNA APPN

03

08

4C80

7083

NetBIOS

03

08

4C80

7084

HPR

03

08

4C80

7085

Bridged Protocols:

 

 

 

 

 

Flag Address Ctrl

NLPID SNAP HeaderType Field Data FCS Flag

IPX

03

80

AA AA 03

81

37

NOVELL

03

80

AA AA 03

81

38

APPLETALK

03

80

AA AA 03

80

9B

Both 802.3 TB (Transparent Bridge) frames and 802.5 SRB (Source Route Bridge) frames use the same NLPID and OUI over frame relay. The difference between the two is the PIDs. All FRX bridged protocols (with the exception of 802.5 SRB) are bridged as 802.3 TB frames (i.e. PID of 0007). Also note that 802.5 SRB frames over frame relay in RFC1490 format are known in IBM terminology as BAN Type 1

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SmartSwitch 1800 4. 0 User Guide, Rev 01

Page 311 Page 313
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Image 312
Cabletron Systems 1800 manual Lapb Sabm
Page 311 Page 313

1800 specifications

Cabletron Systems, a leading player in network management and telecommunications solutions during the late 20th century, introduced several innovative products that played a crucial role in shaping enterprise networking. Among these were the Cabletron FRX6000, FRX4000, and the FRX1800, which delivered advanced features aimed at enhancing network performance, security, and scalability.

The Cabletron FRX6000 was designed as a robust multi-layer switch, ideal for large-scale enterprise environments. It supported extensive routing capabilities, allowing organizations to manage traffic efficiently even under heavy loads. The FRX6000 boasted high throughput rates and low latency, making it suitable for demanding applications. With support for various network protocols, including IP, IPX, and AppleTalk, its adaptability made it a versatile choice for diverse networking needs. Moreover, security features like VLAN support and Access Control Lists (ACLs) provided enhanced protection against potential threats.

Moving to the FRX4000, this model offered a balance between performance and cost-effectiveness. The FRX4000 maintained many of the essential features of its larger counterpart while catering to medium-sized enterprises. It provided Layer 3 routing and could handle multiple simultaneous connections, ensuring seamless communication across departments. The modular design allowed for easy upgrades, enabling businesses to expand their network infrastructure without significant overhauls. This made the FRX4000 an attractive option for organizations looking to optimize their network investments.

Lastly, the FRX1800, designed for small to medium businesses, focused on simplicity and ease of use while still incorporating powerful network management capabilities. Its user-friendly interface made it accessible for organizations lacking extensive IT resources. The FRX1800 provided essential functionalities such as Integrated Layer 2 switching and routing, network monitoring, and basic security features, ensuring that even smaller companies could maintain efficient, reliable networking without overwhelming complexity.

All three models utilized advanced technologies, including a high bandwidth backbone and state-of-the-art switching architecture, to enable fast and reliable data transfer. They also supported Quality of Service (QoS) mechanisms, allowing businesses to prioritize critical applications and ensure consistent performance across the network.

In summary, the Cabletron FRX6000, FRX4000, and FRX1800 were pivotal in enhancing network capabilities, providing organizations with scalable, secure, and high-performance options tailored to their specific needs.
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