Manuale d’uso / di manutenzione del prodotto IXP12xx del fabbricante Intel
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IXP12xx ATM OC12/Ethernet IP Router Example Design Performance and Headroom Analysis April, 2002 Document Number: 301144-001.
Version 1.0 , 4/10/02 Page 2 of 17 Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document.
Version 1.0 , 4/10/02 Page 3 of 17 IXP12xx ATM OC12/Ethernet IP Router Example Design Performance and Headroom Anal ysis OVERVIEW This documents details the performance and h eadroom analysis done on the IXP12xx ATM OC12 / Ethernet IP Router Example Design.
Version 1.0 , 4/10/02 Page 4 of 17 KEY WORKLOADS & APPROACHES TO TESTING THE EXAMPLE DESIGN Protocol Performance of IP over ATM vs. Ethernet Figure 1 details the protocol processing required to carry an IP packet over ATM and Ethernet.
Version 1.0 , 4/10/02 Page 5 of 17 The result is that ATM is significantly more effici ent that Ethernet in terms of Mbps for carrying very small PDUs. Every Mbps of single-cell- PDUs on the ATM link requires (84/55) Mbps on the matching Ethernet link(s).
Version 1.0 , 4/10/02 Page 6 of 17 As shown graphically in Figure 3, 622Mbps of single- cell-PDU input requires 622*(84/55) = 949 Mbps of Ethernet output.
Version 1.0 , 4/10/02 Page 7 of 17 bytes/minimum frame}. 84 bytes/frame * 8 bits/byte / 100Mb/sec = 6.72 usec/frame. 232MHz * 6.72 usec/frame = 1559 cycles/frame These cycle budgets specify how frequently a cell or frame goes over the wire. If multiple threads handle multiple frames on the same wire, then the budgets are multiplied accordingly.
Version 1.0 , 4/10/02 Page 8 of 17 One issue with running simulations unbounded to wi re-rate is that it can hide errors because there is no concept of device overflows or underflows.
Version 1.0 , 4/10/02 Page 9 of 17 Both the OC-12 and 4xOC-3 configurations experi ence an ATM overflow after 1M cycles. This indicates that under this system workload, the r eceiver is not keeping up with the wire, but has dropped a cell in the first 6,000 cells.
Version 1.0 , 4/10/02 Page 10 of 17 the number of times the PHY was not fed a cell in time to keep the wire busy, and thus had to manufacture an idle cell.
Version 1.0 , 4/10/02 Page 11 of 17 degrade in these scenarios, a nd the design becomes subject to ATM overflows from running “_VolgaGetChanCounters”. Ethernet Input Ports ATM Transmit Rate [%] IXF6012 Transmit Idle ATM Receive Ports IXF6012 Overflows Ethernet Transmit KFrame/s Ethernet Transmit [MB/s] 8 84 N/A 1 0 138 - 147 8.
Version 1.0 , 4/10/02 Page 12 of 17 Ethernet Input Ports ATM Transmit Rate [%] IXF6012 Transmit Idle ATM Receive Ports IXF6012 Overflows Ethernet Transmit KFrame/s Ethernet Transmit [MB/s] 8 100 0 1 0 88,300 5.
Version 1.0 , 4/10/02 Page 13 of 17 Queue to Core Measurement Technique The performance of the queue-to-core path can be measured by modifying a nominal input data stream such that the entire stream is forwarded to core. For example, changing the IP version in the IP header from 4 to 5 will cause the packets to be forwarded to the core.
Version 1.0 , 4/10/02 Page 14 of 17 RESOURCE UTILIZATION AND HEADROOM ANALYSIS This section details system resource utilization, including per-microengine resources such as registers and microstore instructions; as well as shared resources such as Scratchpad RAM, SRAM, and DRAM.
Version 1.0 , 4/10/02 Page 15 of 17 Microstore utilization can be observed by openi ng a microengine list window with line num bers enabled, and recording the last line number plus 1. A vailable instructions = 2048 – used instructions. Figure 12 shows the results for each of the three configurations.
Version 1.0 , 4/10/02 Page 16 of 17 SDRAM Capacity The IXM1240 Network Processor Base Card comes with 128MB of SDRAM. The project is configured to use less than 64MB: 32MB of Packet Data Buffers, 16MB for VxWorks, and the balance for IP Route Table Entries.
Version 1.0 , 4/10/02 Page 17 of 17 APPENDIX Buffer Allocation in DRAM The microengines in this example design uses two DRAM command queues. The ordered queue is used by all sdram_crc[] commands to transfer packet data between DRAM and the receive and transmit FIFOs.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Intel IXP12xx è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Intel IXP12xx - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Intel IXP12xx imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Intel IXP12xx ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Intel IXP12xx, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Intel IXP12xx.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Intel IXP12xx. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Intel IXP12xx insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
