EP0500987B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for detecting terminal addresses in a bridge connecting local area networks
Assignee: Siemens AG
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Filing: 1991-02-27
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Granted: 1996-01-31
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Expires: 2011-02-27
Abstract
Abstract The method according to the invention is used for automatic identification of communications terminal addresses (kea) in bridges (NUE) connecting two local area networks. With the aid of a hash method, hash memory addresses (hsa) are calculated from the communications terminal addresses (kea) inserted in the messages packets (pi) which are transferred via the local area networks (LBN, LRN), which hash addresses in each case represent the address of a memory space of a hash storage device (HLB, HVB). Address information (ai) is recorded in the addressed memory space, indicating a memory area (SB) in an address table storage device (LBSP, VBSP). With the aid of validity information (gi), this memory area (SB) is checked for the presence of a communications terminal address (kea). If the same communications terminal address (kea) is already recorded, the detected communications terminal address (kea) is evaluated as identified. If the communications terminal address (kea) is not present, the currently detected address is recorded in the addressed memory space (SB). <IMAGE>
Inventors
- 👤 Werner Dr. Stöckl
- 👤 Klaus Hünlich
- 👤 Roland Walker
- 👤 Hans Dr. Horsmann
- 👤 Helmut Rebstock
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 00:24
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/46; H04L12/4604; H04L12/462; H04L12/4625; H04L2212/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
247 words
Method for recording addresses (kea) of communication terminals (KE) connected to local area networks in bridges (NUE) connecting two local area networks (LRN, LBN) in each case, - in which, with the aid of switching-oriented communication terminal source and destination addresses (kea(u), kea(z)) inserted into the packeted messages (pi), the packeted messages (pi) are switched in the local area networks (LBN, LRN), - in which each communication terminal address (kea) comprising n bits which occurs in the connected local area networks (LBN, LRN) is detected in the bridge (NUE), and from this a hash memory address (hsa) with n-m bits, where n and m are integers and m < n, is calculated using a hashing method, - in which the hash memory address (hsa) represents the address of a memory location, comprising n-m bits, of a hash memory means (HLB, HVN) realized in the bridge (NUE), characterized - in that entered in the addressed memory location is address information (ai) that points to a memory area (SB), comprising n bits, of an address table memory means (LBSP, VBSP) arranged in the bridge (NUE), and - in that if a communication terminal address (kea) is not present in the referended memory area (SB), the currently detected communication terminal address (kea) is stored in said memory area (SB), and if the same communication terminal address (kea) is present the detected communication terminal address (kea) is evaluated as recorded, with the presence or absence being indicated by validity information (gi).
Claim 2
Dependent Claim
214 words
Method according to Claim 1, characterized - in that in bridges (NUE), by means of which either in each case a local area network (LBN) is connected to a local integrated network (VBN) that connects a plurality of local area networks (LBN), or a local integrated network (VBN) is connected to a local integrated network (VBN) that connects further local integrated networks (VBN), its own bridge address (nua (u)) is appended to the packeted messages (pi) in addition to the source communication terminal address (kea(u)), - in that the bridge addresses (nua(u)) transmitted by the local integrated networks (VBN) and assigned to the source communication terminal addresses (kea(u)) are recorded and stored using a hashing method, - in that the recorded bridge addresses (nua), which are assigned to a communication terminal address (kea) in each case, are appended to the respective packeted message (pi) for the purpose of targeted transmission of the packeted messages (pi) to the bridge (NUE) assigned to the destination communication terminal (KE), - in that when packeted messages (pi) are transmitted via local integrated networks (VBN) in which the bridge address (nua) assigned to the destination communication terminal address (kea(z)) has not yet been recorded, broadcast information (rsi) is appended to the packeted messages (pi) in the respective bridges (NUE).
Claim 3
Dependent Claim
92 words
Method according to Claim 2, characterized in that, when transmitted via local integrated networks (VBN), the packeted messages (pi) of the local area networks (LBN) are inserted in each case into the information part (NTV) of the packeted messages (piv) of the local integrated networks (VBN), and in that the bridge addresses (nua) assigned to the source, and destination communication terminal addresses (kea(u), kea(z)) or broadcast information (rsi) are inserted in each case into the destination and source address fields (AFV) of the packeted messages (piv) of the local integrated networks (VBN).
Claim 4
Dependent Claim
130 words
Method according to at least one of the preceding claims, characterized in that after the detection of a communication terminal address (kea) or a bridge address (nua) respectively when a communication terminal address (kea) or bridge address (nua) respectively is present in the memory means (SPE), this address is compared with the detected communication terminal address (kea) or bridge address (nua) respectively for the purpose of determining a communication terminal address or bridge address collision, and if the detected and the stored communication terminal address (kea) or bridge address (nua) respectively are not identical, the detected communication terminal address (kea) or bridge address (nua) respectively is stored in a collision memory area, provided that the detected administrative communication terminal address (kea) or bridge address (nua) respectively is not already stored.
Claim 5
Dependent Claim
60 words
Method according to Claim 4, characterized in that the collision memory area is provided in a separate collision table memory means (KTSP), and, if a communication terminal or bridge address collision is present, a free collision memory area in the collision table memory means (KTSP) is determined and the address thereof is additionally entered in the hash-addressed memory area (SB).
Claim 6
Dependent Claim
61 words
Method according to claim 4, characterized in that the collision memory area is provided in the address table memory means (LBSP, VBSP), and, if a communication terminal or bridge address collision is present, a free collision memory area in the address table memory means (LBSP, VBSP) is determined and the address thereof is additionally entered in the hash-addressed memory area (SB).
Claim 7
Dependent Claim
50 words
Method according to at least one of the preceding claims, characterized in that a hashing algorithm is selected for the hashing method depending on a short calculation time, on the extent of code compression of the communication terminal addresses (kea) and on the communication terminal address space used the most.
Claim 8
Dependent Claim
65 words
Method according to at least one of the preceding claims, characterized in that in the case of a communication terminal address (kea) or bridge address (nua) respectively comprising 48 bits, a hashing algorithm is provided with which the first two lowest order bytes are binary EX-ORed with the second two lowest order bytes of the respective communication terminal address (kea) or bridge address (nua) respectively.
Claim 9
Dependent Claim
30 words
Method according to Claim 8, characterized in that the calculated hash memory address (hsa) is matched to given sizes of the hash memory means by reducing further lower order bits.
Claim 10
Dependent Claim
61 words
Method according to at least one of the preceding claims, characterized in that the hash memory addresses (hsa) are calculated from the detected communication terminal addresses (kea) or bridge addresses (nua) respectively for each specific network and the communication terminal addresses (kea) or bridge addresses (nua) respectively are stored in network-specific address tables in the address table memory means (LBSP, VBSP).
Claim 11
Dependent Claim
94 words
Method according to at least one of the preceding claims, characterized in that in a bridge (NUE) after a destination communication terminal address (kea (z)) contained in a packeted message (pi) sent by a communication terminal (KE) of the associated locally managed network (LBN) has been determined in an address table, which represents the address table of a local area network (LBN) locally managed by a bridge (NUE), the forwarding of the packeted message (pi) to the further local area network (LRN) or local integrated network (VBN) connected to the bridge (NUE) is prevented.
Claim 12
Dependent Claim
70 words
Method according to at least one of the preceding claims, characterized in that the communication terminal addresses (kea) or bridge addresses (nua) respectively recorded in the bridges (NUE) are temporarily stored in the memory means (SPE), it being necessary to match the storage duration to the size of the local area networks (LBN, VBN) and a prescribed flexibility with respect to the configuration of the local area networks (LBN, VBN).
References Cited (Backward Citations)
No citation records indexed.
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