Cisco CRS-1 - Carrier Routing System Router Hardware Installation Guide

3-3
Cisco CRS-1 Carrier Routing System SIP and SPA Hardware Installation Guide
OL-17439-01
Chapter 3 Overview: Cisco CRS-1 Shared Port Adapters
Bandwidth Oversubscription
If you are using only Gigabit Ethernet SPAs on the Cisco CRS-1 SIP-800, then the SIP can be
oversubscribed. The Cisco CRS-1 SIP-800 can pass a maximum of 40 Gbps of traffic, so if you have six
8
-Port Gigabit Ethernet SPAs operating at almost full capacity, the SIP is oversubscribed.
If you are using any Packet Over Sonet (POS) SPAs in the Cisco CRS-1 SIP-800, regardless of the
ba
ndwidth of the SPA interfaces (OC-3c/STM-1, OC-12c/STM-4, OC-48c/STM-16, or
OC-192c/STM-64), no oversubscription of either PLIM ASIC is allowed, nor can the total bandwidth of
the SIP exceed 40 Gbps. For this reason, you can install a maximum of four OC-192c/STM-64 POS
SP
As in the Cisco CRS-1 SIP-800. Two of them must be installed in subslots 0, 1, or 3; the other two
mu
st be installed in subslots 2, 4, or 5. The following arrangement of SPAs within the SIP indicates a
valid configuration that optimizes the use of the available PLIM ASIC bandwidth:
In this example, because at least o
ne OC-192c/STM-64 POS SPA is installed, the maximum bandwidth
allowed on the first PLIM ASIC (associated with subslots 0, 1, and 3) is 20 Gbps, and the total capacity
o
f the SIP is controlled to be 40 Gbps or less. The total bandwidth usage required in this example is
36 Gbps.
The ingress oversubscription of Cisco CRS-1 SIP-800 with ATM SPA is supported in the following
con
ditions:
• The ATM SPAs are allowed to come up even when the total ingress traffic from all the Gigabit
Ethernet SPAs exceeds 40-Gbps capacity when a combination of Gigabit Ethernet SPAs and ATM
SPAs is used.
• Traffic is restricted to 40 Gbps per MSC when even a single POS SPA is inserted. In this case, the
newly inserted ATM SPA is not allowed to come up.
• Overall traffic to a single PLIM ASIC does not exceed 20 Gbps while sending policed traffic on the
Gigabit Ethernet.
• If oversubscription occurs, then the excess ingress traffic might be dropped.
If you attempt to install a SPA that oversubscribes the SIP, the SPA does not power up, and you receive
an erro
r message similar to the following:
LC/0/2/CPU0:Jan 31 11:52:57.335 : jacket[159]: %JACKET-3-RULES_FATAL_ERROR
: SPA subslot 4: FAILED: Not enough bandwidth for 1xOC192 POS/RPR HHSPA with XFP
Table 3-2 provides information about the bandwidth for each port (per-port bandwidth) on a SPA and the
cumulative bandwidth (total bandwidth) for all ports available on the SPA.
Subslot 0:
OC-192c/STM-64 POS SPA
Subslot 1:
OC-192c/STM-64 POS SPA
Subslot 2:
8-Port Gigabit Ethernet SPA
Subslot 3:
Empty
Subslot 4:
8-Port Gigabit Ethernet SPA
Subslot 5:
4-Port OC-3c/STM-1 POS SPA
Ta b l e 3-2 SPA Bandwidth Capacity
SPA Per-Port Bandwidth Number of Ports Total Bandwidth
1-Port Clear Channel OC-3 ATM SPA 155.52 Mbps 1 155.52 Mbps
3-Port Clear Channel OC-3 ATM SPA 155.52 Mbps 3 466.56 Mbps
1-Port Clear Channel OC-12 ATM SPA 622.08 Mbps 1 622.08 Mbps
4-Port OC-3c/STM-1 POS SPA 155.52 Mbps 4 622.08 Mbps
8-Port OC-12c/STM-4 Multirate POS SPA 155.52 Mbps or
622
.08 Mbps
8 5 Gbps
1

Cisco CRS-1 - Carrier Routing System Router Specifications

General

Brand	Cisco
Model	CRS-1 - Carrier Routing System Router
Category	Network Router
Language	English