diff --git a/isisd/isis_constants.h b/isisd/isis_constants.h
new file mode 100644
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+++ b/isisd/isis_constants.h
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+/*
+ * IS-IS Rout(e)ing protocol - isis_constants.h   
+ *
+ * Copyright (C) 2001,2002   Sampo Saaristo
+ *                           Tampere University of Technology      
+ *                           Institute of Communications Engineering
+ *
+ * This program is free software; you can redistribute it and/or modify it 
+ * under the terms of the GNU General Public Licenseas published by the Free 
+ * Software Foundation; either version 2 of the License, or (at your option) 
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,but WITHOUT 
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for 
+ * more details.
+
+ * You should have received a copy of the GNU General Public License along 
+ * with this program; if not, write to the Free Software Foundation, Inc., 
+ * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef ISIS_CONSTANTS_H
+#define ISIS_CONSTANTS_H
+
+/*
+ * Architectural constant values from p. 35 of ISO/IEC 10589
+ */ 
+
+#define MAX_LINK_METRIC               63 
+#define MAX_PATH_METRIC               1023
+#define ISO_SAP                       0xFE
+#define INTRADOMAIN_ROUTEING_SELECTOR 0
+#define SEQUENCE_MODULUS              4294967296
+#define RECEIVE_LSP_BUFFER_SIZE       1492
+
+/*
+ * implementation specific jitter values
+ */
+
+#define IIH_JITTER                    25  /* % */
+#define MAX_AGE_JITTER                 5  /* % */
+#define MAX_LSP_GEN_JITTER             5  /* % */
+#define CSNP_JITTER                   10  /* % */
+#define PSNP_JITTER                   10  /* % */
+
+#define RANDOM_SPREAD           100000.0
+
+/*
+ * Default values
+ * ISO - 10589
+ * Section 7.3.21 - Parameters
+ */
+#define MAX_AGE                       1200
+#define ZERO_AGE_LIFETIME             60
+#define MAX_LSP_GEN_INTERVAL          900
+#define MIN_LSP_GEN_INTERVAL          30
+#define MIN_LSP_TRANS_INTERVAL        5
+#define ISIS_MIN_LSP_LIFETIME         380
+#define CSNP_INTERVAL                 10
+#define PSNP_INTERVAL                 2
+#define ISIS_MAX_PATH_SPLITS          3
+
+#define ISIS_LEVELS                   2
+#define ISIS_LEVEL1                   1
+#define ISIS_LEVEL2                   2
+
+#define HELLO_INTERVAL                1
+#define HELLO_MINIMAL HELLO_INTERVAL
+#define HELLO_MULTIPLIER              3
+#define DEFAULT_PRIORITY              64
+/* different vendors implement different values 5-10 on average */
+#define LSP_GEN_INTERVAL_DEFAULT      10 
+#define LSP_INTERVAL                  33  /* msecs */
+#define DEFAULT_CIRCUIT_METRICS 10
+#define METRICS_UNSUPPORTED 0x80
+#define PERIODIC_SPF_INTERVAL         60 /* at the top of my head */
+#define MINIMUM_SPF_INTERVAL           5 /* .. same here          */ 
+
+/*
+ * NLPID values
+ */
+#define NLPID_IP   204
+#define NLPID_IPV6 142
+
+/*
+ * Return values for functions
+ */
+#define ISIS_OK       0
+#define ISIS_WARNING  1
+#define ISIS_ERROR    2
+#define ISIS_CRITICAL 3
+
+/*
+ * IS-IS Circuit Types
+ */
+
+#define IS_LEVEL_1       1
+#define IS_LEVEL_2       2
+#define IS_LEVEL_1_AND_2 3
+
+#define SNPA_ADDRSTRLEN 18
+#define ISIS_SYS_ID_LEN  6
+#define SYSID_STRLEN    24
+
+/*
+ * LSP bit masks
+ */
+#define LSPBIT_P   0x80
+#define LSPBIT_ATT 0x78
+#define LSPBIT_OL  0x04
+#define LSPBIT_IST 0x03
+
+/*
+ * LSP bit masking macros
+ * taken from tcpdumps
+ * print-isoclns.c
+ */
+
+#define ISIS_MASK_LSP_OL_BIT(x)            ((x)&0x4)
+#define ISIS_MASK_LSP_IS_L1_BIT(x)         ((x)&0x1)
+#define ISIS_MASK_LSP_IS_L2_BIT(x)         ((x)&0x2)
+#define ISIS_MASK_LSP_PARTITION_BIT(x)     ((x)&0x80)
+#define ISIS_MASK_LSP_ATT_BITS(x)          ((x)&0x78)
+#define ISIS_MASK_LSP_ATT_ERROR_BIT(x)     ((x)&0x40)
+#define ISIS_MASK_LSP_ATT_EXPENSE_BIT(x)   ((x)&0x20)
+#define ISIS_MASK_LSP_ATT_DELAY_BIT(x)     ((x)&0x10)
+#define ISIS_MASK_LSP_ATT_DEFAULT_BIT(x)   ((x)&0x8)
+
+#define LLC_LEN 3
+
+/* we need to be aware of the fact we are using ISO sized
+ * packets, using isomtu = mtu - LLC_LEN
+ */
+#define ISO_MTU(C) \
+          (C->circ_type==CIRCUIT_T_BROADCAST) ? \
+          (C->interface->mtu - LLC_LEN) : (C->interface->mtu)
+
+#ifndef ETH_ALEN
+#define ETH_ALEN 6
+#endif
+
+#endif  /* ISIS_CONSTANTS_H */
+
+
+
+
+
+
+
+